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Home My WebLink AboutAPA157I I -----·----I SUSITNA HYDROELECTRIC PROJECT FERC LICENSE APPLICATION EXHIBIT E CHAJYfERS 1 AN 0 2 DRAFT NOVEMBER 15, 1982 I I . ..____._ f.\i_ASKl\ POWER AUTHQR.ITY -_ --_jj ,. .. - (") N ~ L ~' (") g. 0 1.0 1.0 I' (") (") ~ 1~25 ,ss r------------------------------;r411 nll. t5-=t ~------------------------~------------------~ Prepared by~ • SUSITNA HYDROELECTRIC PROJECT FERC LICENSE APPLICATION EXHIBIT E ARLIS CHAPTERS 1 AN:D 2 DRAFT NOVEMBER 15,1982 Alaska Resources Library & Information Services Anchurage. Alaska I -·---'""·,__ __ ALASKA POWER AUTHORITY __ ___,~ 1 -GENERAL DESCRIPTION OF THE LOCALE ARLIS Alaska Resources Library & Information Services Anch..;r~.;;, Alaska !'-1 I - .... ..... SUS ITNA HYDROELECTRIC PROJECT EXHIBIT E VOLUME 1 SECTION 1 GENERAL DESCRIPTION OF THE LOCALE TABLE OF CONTENTS Page 1 -GENERAL DESCRIPTION OF THE LOCALE •••••••••••••••••••••••••• E.l.1 1. 1 -Lac at ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. 1. 1 1.2 -Physiography and Topography •••••••••••••••••••••••••• E.l.1 1.3-GeOlogy and Soils .................................... E.l.l 1.4 -Hydrology ................................. -............ E.1.2 1. 5 -C.l i mate ............... _ ..............•........... -. . . . . E. 1. 2 1.6 -Vegetation .............. ·-·· ........................... E.l.3 1. 7 -W .i 1 d 1 if e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. 1. 3 1.8-Fish ................................................. E.1.4 1. 9 -Land Use ....... : ........... -. . . . . . . • . . . . . . . . . . . . . . . .. . . E. 1. 4 liST OF FIGURES - - - LIST OF FIGURES Figure E.l.l -Location of the Proposed Susitna Hydroelectric Project Figure E.l.2-Vicinities of the Proposed Dam Sites, Susitna Hydroelectric Project Figure E.1.3 Upper Susitna Basin Figure E.l.4-Lower Susitna River Drainage - r - - 1 -GENERAL DESCRIPTION OF THE LOCALE 1.1 -Location The location of the proposed Susitna Hydroelectric Project is within the east to west flowing section of the upper Susitna River,. Alaska, approximately 140 miles north-northeast of Anchorage and 110 miles south-southwest of Fairbanks (Figure E.l.1). Two proposed darns waul d generate electrical power for the railbelt region of Alaska, that is, the corridor surrounding the Alaska Railroad from Seward and Anchorage to Fairbanks. The two proposed darnsites, Watana and Devil Canyon, are 152 and 184 river miles upstream of the river's mouth at Cook Inlet. The nearest sett 1 ements (Go 1 d Creek, Canyon, Chulitna) are along the Alaska Railroad, approximately 12 miles from. Devil Canyon. 1.2-Physiography and Topography The Susitna River basin lies largely within the Coastal Trough province of south-central Alaska, a belt of lowlands extending the length of the Pacific Mountain System and interrupted by the Talkeetna, Clearwater, and Wrangell Mountains. In the vicinity of the proposed impoundments (Figure E. 1.2), the river cuts a narrow, steep-walled gorge up to 1000 feet deep through the Clarence 1 ake Up 1 and and Fog Lakes Up 1 and, areas of broad, rounded summits 3,000 to 4,200 feet in elevation. Between these uplands, the gorge .cuts through an extension of the Talkeetna Mountains, where rugged peaks are 6,900 feet high. Downstream of its confluence with the Chulitna and Talkeetna rivers, near Talkeetna, the Susitna traverses the Cook Inlet-Susitna Lowland, a relatively flat region generally less than 500 feet in elevation. A portion of the proposed transmission facilities, between Healy and Fairbanks, would follow the narrow valley of the Nenana River through the Northern Foot- hi 11 s of the Alaska Range, traverse the Tanana-Kuskokwim Lowland in a flat region generally less than 650 feet in elevation (the Tanana Flats), and then parallel a ridge on the edge of the Yukon-Tanana Up 1 and. 1.3 -Geology and Soils In its complex geologic history, the upper Susitna River region has undergone uplifting and subsidence, marine deposition, volcanic intru- sion, glacial planing and erosion. The Susitna basin 1 ies within the Talkeetna terrain, a zone of moderate seismicity (see Chapter 6). Con- tinuing erosion has removed much of the glacial debris at higher eleva- tions, but very little alluvial deposition has occurred here. The resulting landscape consists of barren bedrock mountains, glacial till-covered plains, and exposed bedrock cliffs in canyons and along streams. Climatic conditions have retarded the development of topsoil. Soils are typical of those formed in cold, wet climates and have devel- oped from glacial till and outwash. They include the acidic, satur- ated, peaty soils of poorly drained ares, the acidic, relatively infer~ tile soils of the forests; and raw gravels and sands along the river. The upper basin is generally underlaid by discontinuous permafrost. E.l. 1 1.4 -Hydrology· The entire drainage area of the Susitna River is about 19,400 square miles of which the upper basin above Gold Creek comprises approximately 6,160 square miles (Figures E.l.3 and E.l.4). Three glaciers in the Alaska Range feed forks of the Susitna River, flow southbound for about 18 miles before joining to form the main stem of the Susitna River. The river flows an additional 55 miles southward through a broad valley where much of the coarse sediment from the glaciers settle out. The river then flows westward about 96 miles through a narrow valley, with the constrictions at Devil Creek and Devil. Canyon areas, creating violent rapids. Numerous small, steep gradient clear-water tributaries flow to the Susitna in this reach of the river. Several of these trib- utaries cascade over waterfalls as they enter the gorge. As the Susitna curves south past Gold Creek, 12 miles downstream of Devil Canyon its gradient gradually decreases. The river is joined about 40 miles beyond Gold Creek in the vicinity of Talkeetna by two major rivers, the Chulitna and Talkeetna. From this confluence, the Susitna flows south through braided channels about 97 miles until it empties into Cook Inlet near Anchorage, approximately 318 miles from its source. Approximately 80 percent of the annual flow occurs between May and September, when the Susitna is heavily laden with glacial silt. Aver- age summer flows at Gold Creek are 20,250 cubic feet per second (cfs); winter flows average only 2100 cfs. In the winter, the river runs clear. The Susitna River above the confluence with the Chulitna River contributes about 20 percent of the mean annual flow measured near the river• s mouth. The upper reaches of the Susitna start to freeze in early October, and by the end of November, the lower river is icebound. Breakup begins in late April or early May, and occasional ice jams may cause the water level to rise as much as 10 feet. · 1. 5 -Climate As in most of Alaska, winters are long, summers are short, and there is considerable variation in daylight between these seasons. Higher ele- vations in the upper basin are characterized by a continental climate typical of interior Alaska. The lower floodplain falls within a zone of transition between maritime and continental climatic influences. From the upper to the lower basin, the climate becomes progressively wetter, with increased cloudiness and more moderate temperatures. At Talkeetna, which is representative of the lower basin, average annual precipitation is about 28 in, of which 68 percent falls between May and October, and annual snowfall is about 106 inches. Monthly average temperatures range from -13°C (9°F) in December and January to 14oC (58°F) in July. E.l. 2 - - - - - - - - - 1.6 -Vegetation The Susitna basin occurs within an ecoregion classified as the Alaska Range Province of the Subarctic Division. The major vegetation types in the upper basin are low mixed shrub, woodland and open black spruce, sedge--grass tundra, mat and cushion tundra, and birch shrub. These vegetation types are typical of vast areas of interior Alaska and northern Canada, where plants exhibit slow or stunted growth in re- sponse to cold, wet, and short growing seasons. Deciduous and mixed conifer-deciduous forests occur at lower elevations in the upper basin, primarily along the Susitna River, but comprise less than three percent of the upper basin area. These forest types have more robust growth characteristics than the vegetation types at higher elevations and are more comparable to vegetation types occurring on the floodplain farther downstream. The floodplain of the lower river is characterized by mature and deca- dent balsam poplar forests, birch-spruce forest, alder thickets, and wi Tl ow-balsam poplar shrub communities. The wi 11 ow-balsam poplar shrub and alder communities are the earliest to establish on new gravel bars, followed by balsam poplar forests and, eventually, by birch-spruce for- est. The-major vegetation types within the proposed transmission cor- ridor from Healy to Fairbanks are closed and open deciduous forests, closed and open mixed forests, and mixed low shrub. 1. 7 -Wildlife Big game in the upper basin include caribou, moose, brown bear, black bear, wolf, and Dall sheep. Caribou migrate through much of the open country in the upper basin, and important calving grounds are present outside of the impoundment zone. Moose are farily common in the vicin- ity of the proposed project, but high qua 1 ity habit at is rather 1 im- ited. Moose also frequent the floodplain of the lower river, espec- (ally in winter. Brown bear occur throughout the project vicinity, while black bear are largely confined to the forested habitat along the river; populations of both species are healthy and productive. Several wolf packs have been noted using the area. Dall sheep generally in- habit areas higher than 3,000 feet in elevation. Furbearer species of the upper basin include red fox, wolverine, pine marten, mink, r-iver otter, short-tailed weasel, least weasel, lynx, muskrat, and beaver. Beavers become increasingly more evident farther downstream. Sixteen species of small mammals that are characteristics of interior Alaska are known to occur in the upper basin. Bird populations of the upper basin are typical of interior Alaska but sparse in comparison to those of more temperate regions. Generally, the forest and woodland habitats support higher densities of birds than do other habitats. In regional perspective, ponds and lakes in the vicinity of the proposed impoundments support relatively few water- birds. Ravens and raptors, including bald and golden eagles, are con- spicuous in the upper basin. Bald eagles also nest along the lower E.l. 3 river. No known peregrime falcon nests exist in or near the reservoir area. One nest exists near the northern leg of the transmission corri-· dar. This nest has not been known to be active since the early l960•s. 1.8 -Fish Anadromous fish in the Susitna basin include all five spec1es of Pacific salmon: pink (humpback); shum (dog); coho {silver); sockeye (red); and chinook (king) salmon. Salmon migrate up the Susitna to spawn in tributary streams, sloughs, and side channels below Devil Canyon. Limited spawning occurs in the mainstem. Surveys to date in- dicate that, except for extremely dry years, salmon are unable to as- cend the Devil Canyon rapids and are thus prevented from migrating farther·into the upper basin. Anadromous smelt (eulachon) are known to migrate into the lower Susitna River, and Bering cisco have recently been discovered. Grayling abound in the clear-water tributaries of the upper basin; these populations are relatively unexploited. Grayling as well as lake trout also inhabit many lakes. The mainstem Susitna has populations of burbot and round whitefish, often associated with the mouths of clear- water tributaries. Dolly Varden, humpback whitefish, sculpin, stick- lebacks, and long-nosed suckers have also been found in the drainage. Rainbow trout, like the anadromous species, have not been found above Devil Canyon. 1. 9 -Land Use Because of 1 imited access, the project area in the upper basin has re- tained a wilderness character. There are no roads to the project vicinity, but there are several off-road vehicle and sled trails. Al- though rough, dirt landing-strips for 1 ight planes are not uncommon, floatplanes provide the principal means of access via the many lakes in the upper basin. Perhaps the most significant land use over the past three decades has been the study of hydropower potential of the Sus itna River. The area is also used by hunters, white-water enthusiasts, fishermen, trappers, and miners. A few wilderness recreation lodges and private cabins, single and in small clusters, are scattered throughout the basin, especially on the larger lakes. Most of the 1 ands in the project area and on the south side of the river have been selected by the Natives under the Alaska Native Claims Settlement Act. Lands to the north are generally federal and are man- aged by the Bureau of Land Management. The State has selected some lands on the north side of the river, and there are many small, scat- tered private holdings in the upper basin. The U.S. Department of the Interior has preserved part of the area within the project impoundment zones as a Power Site Classification (No. 443). £.1.4 - - - - - The transmis·sion corridors outside the dam and impoundment areas (Willow to Anchorage and Healy to Fairbanks) traverse lands with a somewhat higher degree of use. Most of the land within the corridors, however, is undeveloped. E .1. 5 0 1.. LOCATION OF THE PROPOSED SUSITNA HYDROELECTRIC PROJECT LEGEND PRIMARY PAVED UNDIVIDED H IGHWA.Y SECONDARY PAVED UNOIVtOEO HIGHWAY SECONDARY GRAVEl HIGHWAY ~RAilROAD -···--··-WAtERWAY ,6. D•M SITES FIGURE E . 1.1 WATANA ,VIEW UPSTREAM DEVIL CANYON, VIEW UPSTREAM VICINITIES OF THE PROPOSED DAM SITES, SUSITNA HYDROELECTRIC PROJECT FIGURE E.l.2 0 0 z -(/) ~ a:: LLI > a:: <t z 1- CJ) :::> (/) a:: LLI Q. Q. :::> UJ UJ a:: :::::> <.!) LL. 0 Miles 10 LOWER SUSITNA RIVER DRAINAGE FIGURE E .1.4 2 -WATER USE AND QUALITY - - - , .... SUSITNA HYDROELECTRIC PROJECT EXHIBIT E VOLUME 1 CHAPTER 2 WATER USE AND QUALITY TABLE OF CONTENTS 1 -INTRODUCTION E-2-1 2-BASELINE DESCRIPTION ...•................................... E-2-2 2.1-Susltna River viater Quality ................ ; ......... E-2-3 2.2-Susitna River Morphology ............................. E-2-5 2.3 -Susitna River Water Qua 1 i ty .........................• E-2-10 2.4 -Basel-ine Ground Water Conditions ..................... E-2-23 2.5-Existing Lakes, Reservoirs, and Streams .............. E-2-24. 2.6-Existing Instream Flow Uses ...........•.............. E-2-25 2. 7 ·-Access Plan ....................... ; ....... , ............ E-2-29 . 2.8 -Tr ansmi ssi on Corridor ................................. E-2-29 3-PROJECT IMPACT ON WATER QUALITY AND QUANTITY ........•...... E-2-31 3.1-Proposed Project Reservoirs .......................... E-2-31 3.2 -Watana Development ................................... E-2-31 3. 3 -Devil Canyon Development ............................. E-2-68 3 • 4 -Access P 1 an Impact s . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . E-2-86 3.5 -Transmission Corridor Impacts ........................ E-2-88 4-AGENCY CONCERNS AND RECOMMENDATIONS ........................ E-2-89 5 -MITIGATION ENHANCEMENT AND PROTECTIVE MEASURES ............. E-2-90 5.1 -Introduction ........................................• E-2-90 5.2 -Construction .•...................•................... E-2-90 5.3-Mitigation of Watana Impoundment Impacts ............. E-2-90 5.4-Mitigation of Watana Operation Impacts •.............• E~2-91 5.5-Mitigation of Devil Canyon Impoundment Impacts ....... E-2-92 5.6-Mitigation of Devil Canyon/Watana Operation ......•... E-2-92 BIBLIOGRAPHY LIST OF TABLES LIST OF FIGURES ·- - - -' - -· - LIST OF TABLES E. 2. 1 - E. 2. 2 E.2.3 E. 2.4 E. 2. 5 - E.2.6- E. 2. 7 - E.2.8- Gaging Station Data Baseline Monthly Flows (cfs) Instantaneous Peak Flows of Record Comparison of Susitna Regional Flood Peak Estimates With USGS Methods for Gold Creek Sus itna River Reach Definitions Detection Limits for Water Quality Parameters Paraneters Exceeding Criteria by Station and Season 1982 Turbidity Analysis of the Susitna, Chulitna, and Talkeetna Rivers Conf1 uence Area E. 2. 9 -Significant Ion Concentrations E~2.10 -Streams to be Partially or Completely Inundated by Watana Reservoir (El 2,185) · E. 2.11 -Streams to be Partially or Completely Inundated by Devil Canyon Reservoir (El 1,455) E. 2.12 -Downstream Tributaries Potentially Impacted by Project Operation · E. 2. 13 -Summary of Water and Ground Water Appropriations in Equivalent Flow Rates E.2.14-Susitna River-Limitations to Navigation E. 2.15 -Estimated Low and High Flows at Access Road Stream Crossings E.2.16-Available Streamflow Records for Major Streams Crossed by Transmission Corridor E.2.17-Downstream Flow Requirements at Gold Creek E.2.18 -Watana Inflow and Outflow for Filling Cases E.2.19-'Flows at Gold Creek During Watana Filling E.2.20-Monthly Average Pre-Project and Watana Filling Flows at Gold Creek, Sunshine and Susitna Stations E.2.21 -Post-Project Flow at Watana (cfs) E.2.22 -Monthly Maximum, Minimum, and Mean Flows at Watana E.2.23 -Pre-Project Flow at Gold Creek (cfs) E. 2. 24 -Post-Project Flows at Go 1 d Creek E.2.25-Monthly Maximum, Minimum, and Mean Flows at Gold Creek E.2.26-Pre-Project Flow at Sunshine (cfs) £.2.27 -Post-Project Flow at Sunshine (cfs) E.2.28-Pre-Project Flow at Susitna (cfs) E.2.29-Post-Project Flow at Susitna E.2.30-Monthly Maximum, Minimum, and Mean Flows at Sunshine E. 2. 31 -Monthly Max irnllll, Min irnum, and Mean Flows at Susitna E.2.32 -Pre-Project Flow at Watana (cfs) E.2.33 -Pre-Project Flow at Devil Canyon (cfs) E.2.34 -Post-Project Flow at Watana (cfs) E. 2.35 -Post-Project Flow at Devil Canyon (cfs) E.2.36 -Post-Project Flows at Gold Creek (cfs) E.2.37-Monthly Maximl111, Minimum, and Mean Flows at Devil Canyon E.2.38-Post-Project Flow at Sunshine (cfs) E.2.39 -Post-Project Flow at Susitna (cfs) - - LIST OF FIGURES Figure E.2.1 -Data Collection Stations Figure E.2.2 -Annual Flood Frequency Curve~ Susitna River Near Denali Figure E.2.3 -Annual Flood Frequency Curve~ Susitna River Near Cantwell Figure E.2.4 -Annual Flood Frequency Curve, Susitna River at Gold Creek Figure E.2.5 -Annual Flood Frequency Curve, Maclaren River near Paxson Figure E. 2. 6 -Annual Flood Frequency Curve, Chulitna River near Talkeetna Figure E.2.7 -Annual Flood Frequency Curve, Talkeetna River near Talkeetna Figure E.2.8 -Annual Flood Frequency Curve, Skwenta River near Skwentna Figure E.2.9 -Design Dimensionless Regional Frequency Curve Annual Instantaneous Flood Peaks Figure E.2.10-Watana Natural Flood Frequency Curve Figure E.2.11 -Devil Canyon Natural Flood Frequency Curve Figure E.2.12-Flood Hydrographs, May-July Figure E.2.13 -Flood Hydrographs, Aug-Oct Figure E.2.14-Monthly and Annual Flow Duration Curves Susitna River at Gold Creek, Susitna River near Cantwell, Susitna River near Denali Figure E. 2.15 -Monthly and Annual Flow Duration Curves ·Maclaren River at Paxson Figure E.2.16 -Monthly and Annual Flow Duration Curves Susitna River at Susitna Station Figure E. 2.17 -Monthly and Annual Flow Duration Curves Talkeetna River near Talkeenta Figure E.2.18 -Susitna River at Gold Creek, Low-Flow Frequency Curves -May. LIST OF FIGURES (Cont'd) Figure E.2.19-Susitna River at Go1d Creek, Low-Flow Frequency Curves -June Figure E.2.20-Susitna River at Gold Creek, Low-Flow Frequency Curves -July and August Figure E.2.21 -Susitna River at Gold Creek, Low-Flow Frequency Curves -September and October Figure E.2.22 -Susitna River at Gold Creek, High-Flow Frequency Curves -May Figure E.2.23-Susitna River at Gold Creek, High-Flow Frequency Curves -June Figure E.2.24-Su~itna River at Gold Creek, High-Flow Frequency Curves -July and August Figure E.2.25 -Susitna River at Gold Creek, High~Flow Frequency Curves -September· and October Figure E.2.26 -Susitna River Water Temperature-Summer 1980 Figure E.2.27 -Susitna River Water Temperature-Summer 1981 Figure E.2.28-Susitna River at Watana, ~~eekly Average Water Temperature -1981 Water Year Figure E.2.29-Susitna River-Water Temperature Gradient Figure E.2.30 -Data Summary -Temperature Figure E.2.31 -Location Map for 1982 Midwinter Temperature Study Sites Figure E.2.32 -Comparison of Weekly Dial Surface Water Temperature Variations in Slough 21 and the Mainstream Susitna River at Portage Creek (adapted from ADF&G 1981). Figure E.2.33 -Susitna River, Portage Creek and Indian River Water Temperatures Summer 1982 Figure E. 2. 34 -Data Summary -Tota1 Suspended Sediments Figure E.2.35-Suspended Sediment Rating Curves, Upper Susitna River Bas in Figure E.2.36 -Suspended Sediment Size Analysis, Susitna River - LIST OF FIGURES (Contrd) Figure E. 2. 62 -Data Surrmary -Manganese ( t) Figure E. 2. 63 -Data Summary -~lercury (d) Figure E.2.64 -Data Surrmary -Mere ur y ( t ) Figure E. 2. 65 -Data Summary -Ni eke 1 (d) Figure E. 2. 66 -Data Surrmary -Nickel (t} Figure E. 2. 67 -Data Summary -Zinc (d) Figure E. 2. 68 -Data Summary -Zinc ( t} Figure E. 2. 69 -Data Summary -Oxygen, Dissolved. Figure E. 2. 70 -Data Summary -D. a.~ % Saturation Figure E. 2. 71 -Data Summary -Nitrate Nitrogen Figure E. 2. 72 -Data Summary -Ortho Phosphate Figure E. 2. 73 -Location of Township Grids in the Susitna River Basin Figure E.2. 74 -Watana Borrow Site Map Figure E. 2. 75 -Cross:-Section Number 32 Rr~ 130 Figure E.2.76-Watana Water Levels and Gold Creek Flows During Reservoir Filling Figure E.2. 77 -Watana Outflow Frequency Curve During Watana Impoundment (to be completed later) Figure E.2.78-Flow Variability, Natural and filling Conditions Discharge at Gold Creek figure E.2.79-Schematic of the Effect of the Susitna River on Typical Tributary flbuth Figure E.2.80-Eklutna Lake, Light Extinction In Situ Measurements Figure E.2.81 -Slough 9 Thalwg Profile and Susitna River Mainstem Water Surface Profiles Figure E. 2.82 -Watana Reservoir Water Levels (Watana Alone) Figure E.2.83 -Watana Hydrological Data-Sheet 2 - - ·~ - - - - LIST OF FIGURES (Cont•d) Figure E.2.84 -Watana Inflow Flood Frequency Figure E.2.85 "'"Monthly and Annual Flow Duration Curves, Susitna River at Watana Figure E.2.86 -Monthly and Annual Flow Duration Curves, Susitna River at Gold Creek Figure E.2.87 -Monthly and Annual Flow Duration Curves, Susitna River at Sunshine Figure E.2.88 -Monthly and Annual Flow Duration Curves, Susitna River at Susitna Station Figure E.2.89-Water Temperature Profiles, Bradley Lake, Alaska Figure E.2.90 -Multipart Intake Levels Figure E.2.91 -Watana Reservoir Temperature Profiles Figure E. 2. 92 -Reservoir Temperature Modeling, Outflow Temperature Figure E.2.93 -Devil Canyon, Flood Frequency Curve Figure E. 2. 94 -Watana Reservoir Water Levels ( Watana and Devil Canyon in Operation) Figure E.2.95 Devil Canyon Reservoir Water Levels Figure E.2.96 -Devil Canyon Hydrological Data Figure E.2.97 -Monthly and Annual Flow Duration Curves, Talkeetna River Near Talkeetna,Chulitna River near Talkeetna Figure E. 2.98 -Monthly and Annual Flow Duration Curves, Susitna River at Gold Creek Figure E.2.99 -Monthly and Annual Flow Duration Curves, Susitna · River at Sunshine Figure E.2.100-Monthly and Annual Flow Duration Curves, Susitna River at Susitna Station Figure E. 2.101-Temporal Variation in Salinity Within Cook Inlet Near the Susitna River Under Pre-and Post-Susitna Hydroelectric Project Condit ions - ··""' -i - ..... -! 2 -REPORT ON WATER USE AND QUALITY 1 -INTRODUCTION The Report on Water Use and Quality is divided into four basic sec- tions: baseline conditions, project impacts, agency concerns and recom- mendations, and mitigatives, enhancement, and protective measures. Within the sections on baseline conditions and project impacts, emp- hasis is placed on flows, water quality parameters, ground water condi- tions and instream flow uses. The importance of flows cannot be over- stressed. Flows are important to all in stream uses. Mean flows, flood flows, low flows and flow variability are discussed. The primary focus of the water quality discussion is on those para- meters determined most critical for the maintenance of fish populations and other aquatic organisms. Detailed discussions are presented on water temperature both in the mainstem Susitna River and in the sloughs downstream of Devil Canyon, ice, suspended sediment in the reservoirs and downstream, turbidity, dissolved oxygen, nitrogen supersaturation and· nutrients. These parameters have previously been. identified as areas of greatest concern. Mainstem-slough groundwater interaction downstream of Devil Canyon is important to salmonid spawning in sloughs and is discussed. The primary in stream flow uses of the Susitna are for fish, wildlife and riparian vegetation. As these are fully discussed in Chapter 3, they are only briefly discussed in this Chapter. However, other in- stream flow uses including navigation and transportation, waste assimi- lative capacity and freshwater recruitment to estuaries are discussed. Since minimal out of river use is made of the water, Talkeetna being the only town located near the river and not relying on the river for its water supply, only limited discussions have been presented on out of river uses. Project impacts have been separated by development. Impacts, as so- c iated with each development, are presented in chronological order: construction, impoundment and operatic~. The agency concerns and recommendations received to date are sum- marized. The mitigation plan incorporates the engineering and construction meas- ures necessary to minimize potential impacts, given the economic and engineering constraints. E-2-1 2 -BASELINE DESCRIPTION The entire drainage area of the Susitna River is about 19,400 square miles, of which the upper basin above Gold Creek comprises approximate- ly 6160 square miles {Figure E.2.1). Three glaciers in the Alaska Range feed forks of the Sus itn a River, flow southward for about 18 miles and then join to form the Susitna River. The river flows an additional 55 miles southward through a broad valley where much of the coarse sediment from the glaciers settles out. The river then flows westward about 96 miles through a narrow valley, with constrictions at the Devil Creek and Devil Canyon areas, creating violent rapids. Num- erous small, steep gradient, clear-water tributaries flow to the, Susitna in this reach of the river. Several of these tributaries cas:! cade over waterfalls as they enter the gorge. As the Sus itna curves south past Gold Creek, 12 miles downstream of the mouth of Devil Canyon, itsgradient gradually decreases. The river is joined about 40 miles beyond Gold Creek in the vicinity of Talkeetna by two major trib- utaries, the Chulitna and Talkeetna Rivers. From this confluence, the Susitna flm~s south through braided channels about 97 miles until it empties into Cook Inlet near Anchorage, approximately 318 miles from its source. The Susitna River is typical of unregulated northern glacial rivers with high, turbid summer flow and low, clear winter flow. Runoff from snownelt and rainfall in the spring causes a rapid increase in flow in May from the low discharges experienced throughout the winter. Peak annual floods usually occur during this period. Associated with the higher spring flows is a 100 fold increase in sedi- ment transport which persists throughout the summer. The 1 arge sus- pended sediment concentration in the June to September time period causes the river to be highly turbid. Glacial silt contributes most of the turbidity of the river when the glaciers begirt to melt in late spring. Rainfall related floods often occur in August and early September, but generally these floods are not as severe as the spring snow melt floods. As the weather beg ins to cool in the fall, the glacial melt rate de- creases and the flows in the river gradually decrease correspondingly. Because most of the river suspended sediment is caused by glacial melt, the river also beg ins to clear. Freeze up normally begins in October and continues to progress up river through early December. The river breakup generally begins in late Apri1 or early ~lay near the mouth and progresses upstream with breakup at the damsite occurring in mid-May. E-2-2 ~I ·- - 2.1 -Susitna River Water Quality (a) Mean Monthly and Annual Flows Cant inuous historical streamflow records of various record 1 ength (8 to 32 years) exist for gaging stations on the Susitna River and its tributaries: Gages are located at Denali, Cantwell (Vee Canyon), Gold Creek and Susitna Station on the Susitna River; on the Maclaren River near Paxson; Chulitna Station on the Chulitna River; Talkeetna on the Talkeetna River; and Skwentna on the Skwentna River. In 1981 a USGS gaging station was constructed at Sunshine on the Susitna River; however, the streamflow record is of such a short duration it has not been used in most of the hydro'logic analysis. Statistics on river mile, drainage area and years of record are shown in Table E.2.1. The station locations are illustrated in Figure E.2.1. A complete 32 year streamflow data set for each gaging station was generated through a correlation analysis, whereby missing mean monthly flows were estimated (Acres l982a). The resultant monthly and ann ua 1 max ·imum, mean and minimum flows for the 32 year record are presented in Table E.2.2. t4ean monthly flows at the Watana and Devil Canyon damsites were estimated using a 1 inear drainage area-flow rel aticmship between the Gold Creek and Cantwell gage sites. The resultant mean, maxi- mum and minimum monthly flows are also provided in Table E. 2. 2. Comparison of flows indicates that 40 percent of th~ streamflow at Gold Creek originates above the Denali and Maclaren gages. It is in this catchment that the glaciers which contribute to the flow at Gold Creek are located. The Sus itna River above Go 1 d Creek contributes 19 percent of the mean annual flow measured at Susitna Station near Cook Inlet. The Chulitna, and Talkeetna Rivers contribute 20 and 10 percent of the Susitna Station flow respectively. The Yentna provides 40 percent of the flow, with the remaining 11 percent originating in miscel- laneous tributaries. The variation between summer and winter flows is greater than a 10 to 1 ratio at all stations. This large seasonal difference is due to the characteristics of the basin. Glacial melt, snownelt, and rainfall provide the majority of the annual river flow during the summer. At Gold Creek, for example, 88 percent of the annual streamflow occurs during the summer months of May through September. · The max·imum and minimum monthly flows for the months of May through September indicate a high flow variability at all stations on a year to year basis. E-2-3 (b) F loads The most commong causes of floods in the Susitna River. Basin are snownelt or a combination of snownelt and rainfall over a large area. This type of flood occurs between May and July with the majority occurring in June. Floods attributable to heavy rains have also occurred in August, September or October. These floods are augmented by snownelt from higher elevations and glacial run- off. Table E.2.3 presents selected flood peaks at four gaging stations. Figures E.2.2 to E.2.8 illustrate annual instantaneous flood frequency curves for individual stations. A regional flood frequency analysis was conducted using there- corded floods in the Susitna River and its principal tributaries· (R&M, 198la). The resulting dimensionless regional frequency curve is depicted in Figure E.2.9. A stepwise multiple linear regression computer program was used to relate the mean annual instantaneous peak flow to the physiographic and climatic charac- teristics of the drainage basins. The mean annual instantaneous peak flows for the Watana and Devil Canyon damsites were computed to be 40,800 cubic feet per second (cfs) and 45,900 cfs respec-· tively. The regional flood frequency curve was compared to the station frequency curve at Gold Creek (Table E.2.4). As the Gold Creek station frequency curve yielded more conservative flood peaks (i.e. 1 arger), it was used to estimate flood peaks at the Watana and Devil Canyon damsites for floods other than the mean annual f1 ood. The flood frequency cw-ves for Watana and Devil Canyon are presented in Figures E. 2.10 and E. 2. 11. Dimensionless flood hydrographs for the Susitna River at Gold Creek were developed for the May -Ju 1 y snomelt floods and the August -October rainfall floods using the five largest Gold Creek floods occurring in each period (R&M, 1981a). Flood hydrographs for the 100, 500, and 10,000 year flood events were constructed using the appropriate flood peak and the dimensionless hydrograph. Hydrographs for the May -July and August -October flood periods are illustrated in Figures E.2.12 and E.2.13 respectively. Probable maximum flood (PMF) studies were conducted for both the Watana and Devil Canyon damsites for use in the design of project spillways and related faci1 ities. These studies which are based on Susitna Basin climatic data and hydrology, indicate that the PMF peak at the Watana damsite is 326,000 cfs. (c) Flow Variability The variability of flow in a river system is important to all. instream flow uses. To illustrate the variability of flow in the Susitna River~ monthly and annual flow duration curves showing the proportion of time that the discharge equals or exceeds a given value were developed for the four mainstem Susitna River gaging stations (Denali~ Cantwell, Gold Creek and Susitna Station) and three major tributaries (Maclaren~ Chulitna~ and Talkeetna Rivers) (R&M, 1982a). These curves which are based on mean daily flows are illustrated on Figures E.2.14 through E.2.17. E-2-4 - - - .(~ - - - - - - The shape of the monthly and annual flow duration curves is s1m1-· lar for each of the stations and is indicative of flow from north- ern glacial rivers. Streamflow is low in the winter months, with little variation in flow and no unusual peaks. Groundwater con- tributions are the preliminary source of the small but relatively constant winter flows. Flow begins to increase slightly in April as breakup approaches. Peak flows in May are an order of magni- tude greater than in Apr i 1. Flow in May a 1 so shows the greatest variation for any month, as low flows may continue into May before the high snowmelt/breakup flows occur. June has the highest peaks and the highest median flow. The months of July and August have relatively flat flow duration curves. This situation is indica- tive of rivers with strong base flow characteristics, as is the case on the Susitna with its contributions from snowmelt and gla- cial melt during the summer. More variability of flow is evident in September and October as cooler weather becomes more prevalent. The 1-day, 3-day, 7-day and 15-day high and low flow values were determined for each month from May through October for the periods of record at Gold Creek, Chulitna River near Talkeetna, Talkeetna River near Talkeetna and Susitna River at Susitna Station (R&M, 1982a). The high and low flow values are presented for Gold Creek in the form of frequency curves in Figures E.2.18 through E.2.21. May showed the most variability. It is the month when either low winter flows or high breakup flows may occur and thus significant changes occur from year to year. June and July generally exhibited less variability than the late summer months. Flow variability increased in the August through October period. Heavy rainstorms often occur in August, with 28 percent of the annual floods occurring in this month. 2.2 -Susitna River Morphology (a} Mainstem The Susitna River originates in the glaciers of the southern slopes of the central Alaskan Range, flowing 318 miles to its mouth at Cook Inlet. The headwaters of the Susitna River and its major upper tri bu- t aries are characterized by broad braided gravel floodplains below the glaciers, with several meltstreams exiting from beneath the glaciers before they cornbi ne. further downstream. The West Fork Susitna River joins the main river about 18 miles below Susitna Glacier. Below the West Fork confluence, the Susitna River becomes a split-channel configuration with numerous islands. The river is generally constrained by low bluffs for about 55 miles. The Maclaren River, a significant glacial tributary, and the Tyone River, which drains Lake Louise and the swampy lowlands of the southeastern upper basin, both enter the Susitna River from the east. Belov1 the confluence with the Tyone River, the Susitna E-2-5 River flows west for 96 miles through steep-walled canyons before reaching the mouth of Devil Canyon. The river has a high gradient through this reach and includes the ~~atana and Devil Canyon Dam- sites. It is primarily a singl-e channel with ·intermittent is- lands. Bed material primarily consists of large grravel cobbles. The mouth of Devil Canyon, at River Mile (RM) 149 forms the lower limit of this reach. Between Dev i1 Canyon and the mouth at Cook In 1 et, the river has been subdivided into nine separate reaches. These reaches are . identified in Table E.2.5, together with the average slope and predominent channel pattern. These reaches are discussed in more detail below. RM 149 to RM 144 Through this reach, the Susitna flows predominately in a single channel confined by valley walls. At locations where the valley bottom widens, depostion of gravel and cobble has formed mid-chan- nel or side-channel bars. Occasionally, a vegetated island or fragmentary floodplain has formed with elevations above normal flood levels, and has become vegetated. Presence of cobbles and boulders in the bed material aids in stabilization of .the channel geometry. RM 144 .. to RM 139 A broadening of the valley bottom through this reach has allowed the river to develop a split channel with intermittent,· well- vegetated islands. A correlation exists between bankfull stage and mean-annual flood. Where the main channel impinges on valley walls or terraces, a cobble armor layer has developed with a top elevation at roughly bankfull flood stage. At RM 144, a perigla- cial alluvial fan of coarse sediments confines .the river to a single channel. RM 139 to RM 129.5 This river reach is characterized by a well defined split channel configuration. Vegetated islands separate the main channel from side channels. Side channels occur frequently in the alluvial floodplain and receive Susitna water only at flows above 15,000 to 20,000 cfs. Often, valley bottom springs flow into sloughs. There is a good correlation between bankfull stage and the mean annual flood. Where the main channel impinges valley walls or terraces, a cobble · armor 1 ayer has developed with a top el ev at ion at roughly bankfull flood stage. The main channel bed has been frequently observed to be well armoured. E-2-6 - - - -. - - - - - - - - ,... : i i Primary tributaries include Indian River, Gold Creek and Fourth of July Creek. Each has formed an alluvial fan extending into the vallej.t bottom and constricting the Susitna to a single channel. Each constriction has established a hydraulic control po·int that regulates water surface profi 1 es and associ a ted hydraulic . para- meters at v ar yi ng discharges. RM 129.5 to RM 119 River patterns through this reach are similar to those in the pre- vious reach. The most prominent characteristic between Sherman and Curry is that the main channel prefers to flow against the. west valley wall and the east floodplain has several side channels and sloughs. The alluvial fan at Curry constricts the Susitna to a single channel and terminates the above described patterns. A fair correlation exists between bankfull stage and mean annual flood through this reach. Comparison of 1950 and 1980 airphotos reveals occasional local changes in bankl ines and island morphol- ogy. The west valley wall is generally nonerodible and has occasional bedrock outcrops. The resistant boundary on one side of the main channel has generally forced a uniform channel configuration with a well armored perimeter. The west valley wall is relatively straight and uniform except at RM 128 and 125. 5. At these loca- tions, bedrock outcrops deflect the main channel to the east side of the floodplain. RM 119 to RM 104 Through this. reach the river is predominantly a very stable, single incised channel with a few islands. The channel banks are well armored with cobbles and boulders, as is the bed. Several large boulders occur intermittently along the main channel and are believed to have been transported down the valley during glacial ice movement. They provide local obstruction to flow and naviga- tion, but do not have a significant impact on channel morphology. RM 104 to RM 95 At the confluence of the Susitna, Chulitna and Talkeetna Rivers, there is a dramatic change in the Susitna from a split channel to a braided channel. Emergence from confined mountainous basins into the unconfined lowland basin has enabled the river systems to develop 1 aterally. Ample bedload transport and a gradient de- crease also assist in establishing the braided pattern. The Chulitna River has a mean annual flow similar to the Susitna at Gold Creek, yet its drainage basin is about 40 percent smaller. Its glacial tributaries are much closer to the confluence than the Susitna. As it emerges from the incised canyon 20 nril es upstream of the confluence, the river transforms into a braided . pattern E-2-7 I I ll;·i t I ! with moderate vegetation growth on the intermediate gravel bars. At about a midpoint between the canyon and confluence, the Chulitna exhibits a highly braided pattern with no vegetation on intermediate gravel bars~ evidence of recent 1 ateral instability. This pattern continues beyond the confluence and giving the impression that the Susitna is tributary to the dominant Chulitna River. The sp1it channel Talkeetna River is tributary to the dominant braided pattern. Terraces generally bound the broad floodplain~ but provide little control over channel morphology. General floodplai.n instability results from the three river system striving to ba 1 ance out the combined flow and sediment regime. RM 95 to 61 Downstream of the three-river confluence, the Sus itna cant i nues its braided pattern~ \'lith multiple channels interlaced through a sparsely vegetated floodplain. The channel nehrork cons its of the main channel, usually one or two subchannels and a number of minor channels. The main channel meanders irregularly through the wide gravel floodplain and inter- mittently f1 ows against the vegetated floodplain. It has the ability to easily migrate laterally within the active gravel floodplain, as the main channel is simply reworking the gravel that the system previously deposited. When the main channel flows against vegetated bank 1 i nes, erosion is retarded due to the vegetation and/or bank materials that are more resistant to ero- sion. Flow in the main channel usually persists throughout the entire year. Subchannels are usually positioned near or against the vegetated floodplain and are generally on the opposite side of the flood- plain from the main channel. The subchannel s normally bifurcate (split) from the main channel when it crosses over to the opposite· side of the floodplain and terminate where the main channel me- anders back across the f1 oodpl ai n and intercepts them. The sub- channels have smaller geometric dimensions than the main channel, and their thalweg is generally about five feet higher. Their flow regime is dependent on the main channel stage and hydraulic flow controls point of bifurcation. Flow may or may not persist throughout the year. Minor channels are relatively shallow, wide channels that traverse the gravel floodplains and complete the interlaced braided pat- tern. These channels are very unstable and generally short-lived. The main channel is intermittently cantrall ed 1 aterally where it flows against terraces. Since the active floodplain is very wide, the presence of terraces has little significance except for deter- mining the general orientation of the river system. An exception is \</here the terraces constrict the river to a single channel at the Parks Highway bridge. Subchannels are directly dependent on E-2-8 - - - - -I - -· - - - - main channel flow and sediment regime, and generally react the same. Minor channels react to both of the 1 arger channel s• behaviors. RM 61 to RM 42 Downstream of the Kashwitna River confluence, the Sus itn a River branches into multiple channels separated by islands with estab- lished vegetation. This reach of the river has been named Delta Islands because it resembles the distributary channel network common with large river deltas. The multiple channels are forced together by terraces just upstream of Kroto Creek (Deshka River). Through this reach, the very broad floodplain and channel network can be divided into three categories: -Western braided channels; -Eastern split channels; and -Intermediate meandering channels. The western braided channel network is considered to be the main portion of this very complex river system. Although not substan- tiated by river surveys, it appears to constitute the largest flow area and lowest thalweg elevation. The reason for this is that the western braided channels canst itute the shortest distance between the point of bifurcation to the confluence of the Delta Island channels. Therefore it has the steepest gradient and highest potential energy for conveyance of water and sediment. RM 42 to RM 0 Downstream of the Delta Islands, the Susitna River gradient decreases as it approaches Cook In 1 et. The river tends toward a split channel configuration as it adjusts to the lower energy s 1 ope. There are short reaches where a tendency to braid emerges. Downstream of RM 20, the river branches out into delta distribu- tary channels. Terraces constrict the floodplain near the Kroto Creek confluence and at Susitna Station. Further downstream, the terraces have little or no influence on the river. The Yentna River joins the Susitna at RM 28 and is a major contri- butor of flow and sediment. Tides in the Cook Inlet rise above 30 feet and therefore control the water surface profile and to some degree the sediment regime of the lower river. River elevation of 30 feet exists at about RM 20 and corresponds to where the Susitna begins to branch out into its delta channels. · (b) Sloughs Sloughs are spring-fed, perched overflow channels that only convey glacial meltwater from the mainstem during median and high flow E-2-9 I I I periods. At intermediate and low flows~ the sloughs convey clear water from small tributaries and/or upwelling groundwater. Dif- ferences between mainstem water surface elevations and the stream- bed elevation of the side sloughs are notably greater at the up- stream entrance to the slo~gh than at the mouth of the slough. The graidents within the slough are typically greater than the adjacent mai nstem. An alluvial berm separates the head of the slough from the river, whereas the ~v-ater surface elevation of the mainstem generally causes a backwater effect at the mouth of the slough. The sloughs function like small stream systems. Several hundred feed of channel exist in each slough conveying water independent of mainstem backwater effects. The sloughs vary in length from 2,000 -6,000 feet. Cross~sec tions of sloughs are typically rectangular with flat bottoms. At the head of the sloughs, substrates are dominated by boulders and cobbles (8-14 inch diameter). Progressing towards the slough mouth, substrate particles reduce in size with gravels and sands predominating. Beavers frequently inhabit the sloughs. Active and abandoned dams are visible. Vegetation commonly covers the banks to the waters edge with bank cutting and slumping occurring during spring break-up flows. The importance of the sloughs as salmon spawning habitat is discussed in detail in Chapter 3. 2.3-Susitna River Water Quality As previously described in Section 2.2, the Susitna River is charac- terized by large seasonal fluctuations in discharge. These flow varia- tions along with the glacial origins of the river essentially control the water quality of the river. Existing water quality data have been compiled for the mai nstem Susitna River from stations located at Denali, Vee Canyon, Gold Creek, Sun- shine, and Susitna Station. In addition, data from two Susitna River tributaries, the Chulitna and Talkeetna Rivers, have also been compiled {R&M, 1982b). The station locations are presented in Figure E2.1. Data were compiled corresponding to three seasons: breakup, summer, and winter. Breakup is usually short and-extends from the time ice begins to move down river until recession of spring runoff. Summer extends from the end of breakup unt i 1 the water temperature drops to essentially 0°C in the fall, and winter is the period from the end of summer to breakup. The water quality parameters measured and their respectively detection limits appear in Table E.2.6. The water quality was evaluated (R&M 1982b) using guidelines and cri- teria established from the following references: -ADEC, Water Quality Standards. Alaska Department of Environmental Conservation, Juneau, Alaska, 1979. -EPA, Quality Criteria For Water. U.S. Environmental Protection Agency, Washington, D.C., 1976. E-2-10 -- - - - - - - - -' 1.- - - - ~I -McNeely, R.N., V.P. Neimanism abd K, Dwyer. Water Ql.lality Source- book--A Guide to Water Quality Parameters. Environment Canada, Inland Waters Directorate, Water Quality Branch, Ottawa, .Canada, 1979. -Sitting, Marshall. Handbook of Toxic and Hazardous Chemicals. Noyes Publications, Park Ridge, New Jersey, 1981. -EPA, Water Quality Criteria Documents; Avail abi 1 ity. Environmental Protection Agency, Federal Register, 45, 7931S-79379 (November 28, 1980). The guidelines or criteria used for the parameters were chosen based on a priority system. Alaska Water Quality Standards were the first choice, followed by criteria presented in EPA's Quality Criteria for Water. If a criterion expressed as a specific concentration was not presented in the above two references, the other cited references were used as the source. A second priority system was used for selecting the guidelines or cri- teria presented for each parameter. This was required because the various references presented above cite 1 evel s of parameters that provide for the protection of identified water uses, such as (1) the propagation of.fish and other aquatic organisms, {2) water supply for drinking, food preparation, industrial processes, and agriculture, and (3) water recreation. The first priority, therefore, was to present the guidelines or criteria that apply to the protection of freshwater aquatic organisms. The second priority was to present levels of para- meters that are acceptable for water supply, and the third priority was to present other guidelines or criteria if available. It should be noted that water quality standards set criteria which limit man-induced pollution to protect identified water uses. Although the Susitna River basin is a pristine area,. some parameters naturally exceeded their respective criterion. These parameters are presented in Table E.2.7. As noted in Tab 1 e E. 2. 7, criteria for three parameters have been set at a level which natural waters usually do not exceed. The suggested criteria for alumim.nn and bismuth are based on human health effects. The criterion for total organic carbon (TOC) was established at 3 mg/1. Water containing less than this concentration has been observed to be relatively clean. However, streams in Alaska receiving tundra runoff commonly exceed this level. The maximum TOC concentration reported herein, 20 mg/1, is likely the result of natural conditions. The criterion for manganese was established to protect water supplies for human consumption. The criteria presented for the remaining parameters appearing in Table E.2.7 are established by law for protection of freshwater aquatic organisms. The water quality standards apply to man-induced alter at ions and canst itute the degree of degradation which may not be exceeded. Because there are no industries, no significant agricultural areas, and no major cities adjacent to the Susitna, Talkeetna, and Chulitna Rivers, the measured levels of these parameters are considered to be natural conditions. Since criteria exceedance is attributed to natural conditions, little additional discussion will be given to these phenomenon. Also, these rivers suppm·t diverse E-2-11 populations of fish and other aquatic life. Consequently~ it is con- cluded that the parameters exceeding_ their criteria probably do not have significant adverse effects on aquatic organisms. In the fo1lowing discussion, parameters measured during breakup will generally not be discussed since data normally indicate a transition period between the winter and summer extremes and the data itself is usually limited. Levels of water quality parameters discussed in the following section are reported by R&M (1982b), unless otherwise noted. {a) Physical Parameters ( i) Water Temperature -Mainstem In general, during winter, the entire mainstem Susitna River is at or near 0°C. However, there are a number of small discontinuous areas with groundwater inflow of near 2°C. As spring breakup occurs the water temperature begins to rise, generally warming with distance downstream.· In summer, glacial melt is near OoC as it leaves the glacier, but as it flows across the wtde gravel flood- plain below the glaciers the water begins to warm. As the water winds its way downstream to the proposecj Watana damsite it can reach temperatures as high as 14"C. Further downstream there is generally some additional warming but, temperatures may be cooler at some locations due to the effect of tributary inflow. In August, temperatures begin to drop, reaching OoC in 1 ate September or October. The seasonal temperature variation for the Susitna River at Denali and Vee Canyon during 1980 and for Denali and Watana during 1981 are displayed in Figures _E.2.26 and E.2.27. Weekly averages for Watana in 1981 are shown in Figure E. 2. 28. The shaded area ·indicates the range of temperatures measured on a mean daily basis. The temperature variations for eight summer days at Denali, Vee Canyon and Susitna Station are presented in Figure E.2.29_. The recorded variation in water temperatures at the seven USGS gaging stations is displayed in Figure E.2.30. Additional data on water temperature are available in the annual reports of U.S .G.S. Water Resources Data for Alaska, the Alaska Department of Fish and Game (ADF&;G) Susitna Hydroelectric Project data reports (Aquatic Habitat and Instream Flow Project -1981, and Aquatic studies Program -1982), and in Water Quality Data - 1981 b, 1981-c, R&M Consultants. E-2-12 - - - ~I - - - - - .-1 -Sloughs The sloughs downstream of Devil Canyon have a temperature regime that differs form the mainstem. During the winter of 1982 i ntergravel and surface water temperatures were measured in sloughs SA, 9, 11, 19, 20 and 21, the loca- tions of which are illustrated in Figure E. 2. 31. These measurements indicated that intergravel temperatures were relatively constant through February and March at each location but exh'fbited some variability from one location to another. At most stations intergravel temperatures were within the 2-3°C range. Slough surface temperatures showed more variability at each location and were generally lower than intergravel temperatures during February and March (Trihey, 1982a). During spring and summer, when flow at the he ad of the slough is cut off, slough temperatures tend to differ from mainstem temperatures. During periods of high flows, when the head end is overtopped, slough water temperatures correspond more closely to mainstem tempera- tures. Figure E.2.32 compares weekly diel surface water temperature variations during September, 1981 in Slough 21 with /the mainstem Susitna River at Portage Creek· (ADF&G, 1982). The slough temperatures show a marked diurnal variation caused by increased solar warming of the st:!allow water during the day and subsequent long wave back radiation at night. Mainstem water temperatures are more constant because of the buffering and mixing capability of the river. Tributaries The tributaries to the Susitna River generally exhibit cooler water temperatures than does the mainstem. Con- tinuous water temperatures have been monitored by the USGS in the Chulitna and Talkeetna Rivers near Talkeetna, and ·also by ADF&G in those two rivers as well as in Portage, Tsusena, Watana, Kosi na, and Goose Creeks, and in Indian and the Oshetna River. The 1982 mean daily temperature records for Indian River and Portage Creek are compared in Figure E.2.33. Portage Creek was consistently cooler than Indian River by 0.1 to 1. 9°C. The flatter terrain in the lower reaches of the Indian River valley is apparently more conducive to solar and connective heating than the steep-walled canyon of Portage Creek. Figure E. 2. 33 also presents v-Jater temper- ature data from the main stem' Susitna for the same period, showing the consistently warmer temperatures in the main- stem. E-2-13 There are noticeable diurnal flucutations in the open· water tributary temperatures, though not as extreme as in the sloughs .. Daily variation of up to 6.5°C (from 3.0 to 9. 5°C) was observed at Portage Creek in 1982 (June 14). The major tributaries joining the Susitna at Talkeetna show uniform variation in temperatures from the mainstem. Compared to the Talkeetna fishwheel site on the Susitna, the Talkeetna River temperature· is 1-3°C cooler on a daily average basis. The Chulitna River, being closer to its glacial headwaters, is from 0 to 2oC cooler than the Talkeetna river, and has less during fluctuations. Winter stream temperatures are expected to be very close to DoC, as all the tributaries do freeze up. Groundwater inflow at some 1 ocat ions may create 1 ocal conditions above freezing, but the overall temperature regime would be affected by the extreme co 1 d in the environment. (ii) Ice -Freeze--up Air temperatures in the Susitna basin increase from the headwaters to the lower reaches. While the temperature gradient is partially due to the two-degree latitudinal span of the river, it is, for the most part due to the 3, 300-foot difference in elevation between the 1 ower and upper basins, and the climate-moderating effect of Cook In 1 et on the 1 ower river reaches. The gradient results in a period (late October -early November) in which the air temperatures in the lower basin are above freezing while subfreezing in the upper basin. The location of freezing air temperatures moves in a downstream direction as winter progresses (R&M, 1982c). Frazil ice forms in the upper segment of the river first, due to the initial cold temperatures of glacial melt and the earlier cold air temperatures. Additional frazil ice is generated in the fast-flowing rapids between Vee Canyon and Devil Canyon. The frazil ice generation nor- mally continues for a period of 3-5 weeks before a solid ice cover forms in the 1 ower river, often a result of frazil-ice pans and floes jamming in suitab 1 e reaches. Once frazil ice jams form, the ice cover progresses up- stream, often raising water levels by 2 to 4 feet. Bor- der ice formation along the river banks also serves to restrict the channel. E-2-14 - '~ - ~' -· - - - !"""' I The upper Susitna. River is the primary contribl)tor of ice to the river system below Talkeetna~ contributing 75-85 percent of the ice load in the Susitna-Chulitna-Talkeetna Rivers. Ice format ion on the Chulitna and Talkeetna Rivers normally commences several weeks after freeze-up on the middle and upper Susitna River. -Winter Ice Conditions Once the solid ice cover forms, open leads still occur ·in areas of high-ve 1 oc ity water or groundwater up we 11 ing. These leads shrink during cold weather and are the last areas in the main channel to be completely covered by ice. Ice thickness increases throughout the winter. The ice cover averages over 4 feet thick by breakup~ but . thicknesses of over 10 feet have been recorded near Vee Canyon. Some of the side-channels and sloughs above Talkeetna do not form an ice cover during winter due to groundwater exfiltration. Winter groundwater temperatures generally varying between zoe to 4 oc contribute enough heat to prevent the ice cover from forming (Trihey 1982a}. These areas are often salmonid egg incubation areas. -Breakup The onset of warmer air temperatures occurs in the lower basin several weeks earlier than in the upper basin, due to the temperature gradient previously noted. The low- elevation snowpack melts first, causing river discharge to increase. The rising water level puts pressure on the ice, causing fractures to develop in the ice cover. The severity of breakup is dependent on the snowmelt rate, on the depth of the snowpack and the amount of rainfall, if it occurs. A 1 ight snowpack and warm spring temperatures result in a gradual increase in river discharge. Strong forces on the ice cover do not occur to initiate ice movement resulting in a mild breakup, as occurred in 1981 (R&M, 1981d}. Conversely, a heavy snowpack and cool air temperatures into late spring, followed by a sudden increase in air temperatures may result in a rapid rise in water level. The rapid water level increase initiates ice movement and this movement coupled with ice left in a strong condition from the cooler temperatures leads to numerous and possibly severe ice jams which may result in flooding and erosion, as occurred in 1982 (R&M, 1982f). The flooding results in high flows through numerous side- channels in the reach above Talkeetna. The flooding and erosion during breakup are believed to be the primary factors influencing river morphology in the reach between Dev i 1 Canyon and Talkeetna (R&M, l982a). E-2-15 (iii) Suspended Sediments The Susitna River and many of its major tributaries are glacial rivers which experience extreme fluctuations in suspended sediment concentrations as the result of both glacial melt and runoff from rainfall or snownelt. Beg inn..:. ing with spring breakup, suspended sediment concentrations begin to rise from their near zero winter levels. During summer, values as high as 5700 mg/l have been recorded at Denali, the gaging station nearest the glacially-fed head- waters. Before entering the areas of the proposed reser- voirs, concentrations decrease due to the inflow from several clear water tributari-es. Maximum summer concentra- tions of 2600 mg/1 have been observed at Gold Creek. Below Talkeetna, concentrations increase due to the contribution of the sediment-laden Chulitna River which has 28 percent of its drainage area covered by year round ·ice. Maximum values of 3000 mg/1 have been recorded at the Susitna Sta- tion gage. A more extensive summary of suspended sediment concentrations is presented in Figure E.2.34. Suspended sediment discharge has been shown to increase with discharge (R&M, l982d). This relationship for various upper Susitna River stations is illustrated in Figure E. 2. 35. Estimates of the average annual suspended sediment .load for three locations on the upper Susitna River are provided in the following table (R&M, l982d). Gaging Station Susitna River at Denali Susitna River near Cantwell Susitna River at Gold Creek Average Annual Suspended Sediment Load (tons/year) 2,965,000 6,898,000 7,731,000 The suspended sediment 1 oad entering the proposed Watana - - - - - - Reservoir from the Susitna River is assumed to be that at - the gaging site for the Susitna River near Cantwell, or 6,898, 000 tons/ year (R&M, 1982d). A suspended sediment size analysis for upper Susitna River stations is presented in Figure E.2.36. The analysis indicates that between 20 and 25 percent of the suspended sediment is less than 4 microns (.004 millimeters) in ·diameter. E-2-16 - - - - - - - . , .... (iv) Turbidity ( v) -Mainstem The Susitna River is typically clear during the winter months with values at or very near zero. Turbidity increases as snownelt and breakup commence. The peak turbidity values occur during summer when glacial input is greatest. Limited turbidity data are available for the headwaters of the Sus itna River. However, measurements up to 350 Nephelometer Turbidity units (NTU) have been recorded at Denali. Turbidity tends to decrease in the vicinity of the project areas due to clearwater inflow, although high values sti 11 exist. At the mouth of the Chulitna River near Talkeetna, values of over 1900 NTU have been observed. In contrast, maximum observed values on the Talkeetna River, with its minimal glacial ·input, were 270 NTU. Results of data collection are summarized in Figure E.2.37 (R&M, 1982e). Data collected at various sites in 1982 are tabulated in Table E.2.8. Figure E.2.38 shows the direct relationship between sus- pended sediment concentation and turbidity as measured on the Susitna River at Cantwell, Gold Creek, and Chase (Peratrovich, Nottingham and Drage, 1982a). However, suspended sediment concentrations can vary significantly at similar flow ranges, as the. glaciers contribute highly variable amounts of sediment (R&M, 1982d). -Sloughs Turbidity values for selected sloughs were collected by ADF&G during the summer of 1981. The turbidity in the sloughs was less than the turbidity in the mainstem except when upstream ends were overtopped at which time the turbidities usually mirrored main stem levels (ADF&G, 1982). Even with overtopping, some sloughs maintained lower turbidity due to groundwater or tributary inflow. Vertical Illumination Vertical illumination through thee water column varies directly with turbidity and suspended sediment concentra- tion and hence follows the same temporal and spatial patterns. Although no quantitive assessment was conducted, summer vertical illumination is generally a few inches. During winter months, the river bottom can be seen in areas without-ice cover, as the river is exceptionally clear . Vertical illum·inat·ion under an ice cover is inhibited, especially if the ice is not clear and if a snow cover exists over the ice. E-2-17 (vi) Total Oissolved Solids (TDS) Dissolved solids concentratons are higher, and exhibit a wider range during the winter low-flow periods than during the summer period. Data at Denali range from 110-270 mg/1 in the winter and from 40-170 mg/1 in the summer. Pro- gressing downstream on the Susitna River basin, TDS concentrations are generally 1 ower. Gold Creek TDS winter values are 100-190 mg/1, while summer concentrations are 50-140 mg/1. Measurements at Susitna Stat ion, range from 100-140 mg/1 during winter and between 55 and 80 mg/1 in the summer. Figure E.2.39 provides a graphic representation of the data collected. {vii) Specific Conductance {Conductivity) Sus itn a River conductivity values are high during winter low-flow periods and low during the summer. In the up- stream reaches where glacial input is most significant, conductivity is genera.lly higher. At Denali, values range from 190-510 umhos/cm in the winter and from 120-205 umhos/cm in the surnmer. Below Devil Canyon, conductivity values· range from 160-300 umhos in the winter and from 60-230 umhos/ em in the summer. The Chulitna and Ta 1 keetna Rivers have sl ighl y lower con- ductivity values, but are in the same range ·as in the Susitna River. · Figure E.2.40 graphically provides the maximum, minimum and the mean values as we1l as the number of conductivity ob- servations for the seven gaging stations. {viii) Significant ions Concentrations of the significant ions are generally low to moderate, with summer concentrations lower than winter con- centrations. The ranges of concentrations recorded up- stream of the project at Denali and Vee Canyon and down- stream of the project at Gold Creek, Sunshine and Susitna Station are listed in Table E.2.9. The ranges of ion con- centrations at each monitoring station are presented in Fi gure.s E. 2. 41 to E. 2. 46. (ix) pH Average pH values tend to be slightly a1kaline with values typically ranging between? and 8. A wider range is gener- ally exhibited during the spring breakup and summer months with values occasionally dropping below 7. This phenomenon is common in Alaskan streams and is attributable to the actdic tundra runoff. E-2-18 ~I - - - - - - .. -- - Winter pH ranges at the Gold Creek station and 8.1 while the range of summer values is 6.6 Figure E.2.47 displays the pH information stations of record. (x} Total Hardness are between 7. 0 to 8 .1. for the seven Waters of the Susitna River are moderately hard to hard in the winter, and soft to moderately hard during br-eakup and summer. In add it ion, there is a general trend toward softer water in the downstream direct ion. Total hardness, measured as calcium magnesium hardness and reported in terms of CaC03, ranges between 60-120 mg/ 1 at Gold Creek during winter, and betwen 30-105 mg/1 in the summer. At Susitna Station, winter values are 70-95 mg/l while summer values range from 45 to 60 mg/1. Figure E.2.48 presents more detailed total hardness infer- mat ion. (xi) Total Alkalinity Total A"lkal inity concentrations with bicarbonate typically being the only form of alkalinity present, exhibit moderate· to high levels and display a much larger range during winter than the low to moderate summer values. In addition, upstream concentrations are generally 1 arger than downstream values. Winter values at Gold Creek range between 45 and 145 mg/1, while summer values are in the range of 25 to 85 mg/ l. In the lower river at Susitna Station, winter concentrations are between 60-75 mg/1 and summer 1 evel s are in the range of 40-60 mg/ 1 . Figure E.2.49 displays a more deta-Iled description of total alkalinity concentrations. (xii) True Color True color, wider range attributable teristically measured in platinum cobalt units, displays a during summer than winter. This phenomenon is to organic acids (especially tannin) charac- present in the summer tundra runoff. Color levels at Gold Creek vary between 0 and 10 color units during winter and 0 to 40 units in the summer. It is not uncommon for col or 1 evel s in Alaska to be as high as 100 units for streams receiving tundra runoff, i.e., the maximum recorded value at the Sunshine gauge. Figure E.2.50 displays the data collected. E-2-19 (xiii) Metals The concentrations of many metals monitored in the river were low or within the range characteristic of natural waters. Eight parameters antimony (sb}, boron (B), gold (Au), dissolved molybdenum (M), plat inurn (Pt), tin (SnL vanadium (V) and zirconium (Zr) were below detectable 1 imits. However, the concentrations of some trace elements exceeded water quality guidelines . for the protection of freshwater organisms. (Table E.2.4). These-concentrations are the result of natural processes, since with the exception of some placer mining activities, there are no man-induced sources of these elements in the Sus itna River basin. Metals which have exceeded these limites include aluminum (Al}, copper (Cu), iron (Fe); lead (Pb), manganese (Mn), mercury {Hg), nickel {Ni) and zinc {Zn). · . . Figures E.2.51 through E.2.68 summarize the heavy metal data that were collected. (b) Dissolved Gases (i) DissolvedOxygen Dissolved oxygen (0.0.) concentrations generally remain quite high throughout the drainage basin. Winter values average near 13 mg/l while summer concentrations average between 11 and 12 mg/l. These concentrations equate· to dissolved oxygen saturation levels generally exceeding 80 percent, although summer values average near 100 percent. Winter saturation levels decline slightly from summer levels, averaging near 97 percent at Gold Creek and 80 percent at Susitna Station. Figures E.2.69 and E.2.70 contain additional dissolved oxygen data. (ii) Nitrogen Supersaturation Limited sampling for dissolved gas concentrations, namely nitrogen and oxygen, was performed during the 1981 field season. However, continuous monitoring equipment was installed in the vicinity of Devil Canyon for approximately two months (8 August -10 October) during 1982. This data is not available at this t·ime but will be included when it is available. The 1981 data indicated that supersaturation ex is ted above Devil Canyon as well as bel ow ranging from 105.3 percent to 116.7 percent, respectively. Alaska water quality statutes call for a maximu.'TI dissolved gas concentration of no higher than 110 percent. E-2-20 - - - - - {c) .- - (d) - - .~ - Nutrients Nutrient concentrations, specifically nitrate nitrogen and ortho- phosphate, exist in low to moderate concentration throughout the Susitna River. Nitrate concentrations are less than 1.0 mg/1 along the Susitna, although Talkeetna River values have reached 2.5 mg/1. Gold Creek nitrate concentrations vary from below detectable limits to 0.4 mg/1. Biologically available orthophosphates are generally less than 0.2 mg/1 throughout the drainage basin. Go 1 d Creek orthophosphate values vary from below detectable limits to 0.1 mg/1. most values at Vee Canyon are also in this range. This data is depicted in Figures E.2.71 and E.2.72. Studies of glacially influenced lakes in Alaska (Koenings and Kyle, 1982) and Canada (St. John et al., 1976) indicate that over 50 percent of the total phosphorus concentration in the 1 akes studied was biologically inactive. This was attributed to the fact that the greatest percentage of the lakes' total· phosphorus occurred in the particulate form. Consequently, phosphorus available in the dissolved form is much less than recorded values. This is discussed in more detail by Peterson and Nichols, {1982). Of the major nutrients--carbon, silica, nitrogen and phosphorus, the limiting nuturient in the Susitna River is phosphorus (Peterson and Nichols 1982). Other Parameters ( i) ( i i) Chlorophyll-a Chlorophyll-a. as a measure of algal biomass is quite low due to the poor light transmissivity of the glacial waters. The only chlorophyll-a data avail able for the Susitna River were collected at the Susitna Station gage. Values up to 1. 2 mgfm3 for chlorophyll-a (periphyton uncorrected) have been recorded. However, using the chromospectropic technique, values ranged from 0.004 to 0.029 mgfm3 for three samples in 1976 and 1977. All recorded values from 1978 through 1980 were less than detectable 1 imits when analyzed using the chromographic fl uororrieter technique. No data on chlorophyll-a are available for the upper basin. However, with the very high suspended sediment concentra- tions and turbidity values, it is expected that chloro- phyll-a values are very low. Bacteria No data are avail able for bacteria in the upper river basin. Ho\vever, because of the glacial origins of the river and the absence of domestic, agricultural, and industrial development in the watershed, bacteria levels are expected to be quite low. E-2-21 Only limited data on bacterial indicators are available from the lower river basin~ namely for the Talkeetna River since 1972, and from the Susitna River at Susitna Station since 1975. Indicator organisms monitored include total coliforms, fecal coliforms, and fecal streptococci.· Total coliform counts were generally quite low, with all three samples at Susitna Station and 70 percent of the samples on the Talkeetna River registering less than 20 colonies per 100 ml. Occasional high values have been recorded during summer months, with a maximum value of 130 colonies per 100 ml. Fecal coliforrns were also low, usually registering less than 20 colonies per 100 m1. The maximum recorded summer values were 92 and 91 colonies per 100 ml in the Talkeetna and Susitna Rivers, respectively. Fecal streptococci data also display the same pattern; low values in winter months, with occasional high counts during the summer months. All recorded values are believed to reflect natural varia- t'ion within the river, as there are no significant human influences throughout the Sus itna River Bas in that waul d affect bacterial counts. {iii) Others Concentrations of organic pesticides and herbicides, uranium, and gross alpha radioactivity were either less than their respective detection limits or were below levels considered to be potentially harmful. Since no significant sources of these parameters are known to exist in the drainage basin, no further disc~ssions will be pursued. (e) Water Quality Summary The Susitna River is a fast flowing~ cold-water glacial stream of the calcium bicarbonate type containing soft to moderately hard water during breakup and summer, and moderately hard water in the winter. Nutrient concentrations, namely nit rate and orthophos- phate, exist in low-to-moderate concentrations. Dissolved oxygen concentrations typically remain high,· averaging about 12 mg/1 dur- ing the summer and 13 mg/1 during winter. Percentage saturation of dissolved oxygen generally exceeds 80 percent and averages near 100 percent in the summer. Winter saturation levels decline slightly from the summer levels. Typically, pH values range between 7 and 8 and exhibit a wider range in the summer compared to the winter. During summer, pH occasionally drops below 7, which is attributed to organic acids in the tundra runoff. True color, also resu1ting from tundra runoff, displays a wider range E-2-22 - - - - - - - - - - - - - during summer than winter. Values have been measured as high as 40 color units in the vicinity of the damsites. Temperature remains at or near ooc during winter, and the summer maximum is 14°C. Alkalinity concentrations, with bicarbonate as the dominant anion, are low to moderate during summer and moderate to high during winter. The buffering capacity of the river is relatively low on occasion. The concentrations of many trace e 1 ements moni tared in the river were low or within the range characteristics of natural waters. However, the concentrations of some trace e 1 ements exceeded water quality guidelines for the protection of freshwater aquatic organ- isms. These concentrations are the result of natural processes because with the exception of some placer mining activities there are no man-induced sources of these elements in the Susitna River Basin. Concentrations of organic pesticides and herbicides, uranium, and gross alpha radioactivity were either less than their respective detection limits or were below levels considered to be potentially harmful to acquatic organisms. 2.4-Baseline Ground Water Conditions (a) (b) Description of Water Table and Artesian Conditions The landscape of the upper basin consists of relatively barren bedrock mountains with exposed bedrock cliffs in canyons and along streams, and areas of unconsolidated sediments {outwash, t i 11, . alluvium) with low relief particularly in the valleys. The arctic climate has retarded development of topsoil. Unconfined aquifers exist in the unconsolidated sediments, although there is no water table data in these areas except in the relict channel at Watana and the south abutment at Devil Canyon. Winter 1 ow flows in the Susitna River and its major tributaries are fed primarily from ground water storage in unconfined aquifers. The bedrock within the basin comprises crystalline and metamorphic rocks. No significant bedrock aquifers have been identified or are anticipated. Below Talkeetna, the broad plain between the Talkeetna Mountains and the Alaska Range generally has higher ground water yields, with the unconfined aquifers i mmed i at ely adjacent to the Susitna River having the highest yields (Freethey and Scully, 1980). Hydraulic Connection of Ground Water and Surface Water Much of the ground water in the system is stored in unconfined aquifers in the valley bottoms and in alluvial fans along the slopes. Consequently, there is a direct connection between the ground water and surface water. Confined aquifers may exist within some of the unconso1 i dated sediments, but no data are available as to their extent. E-2-23 (c) Locations of Springs, Lvells, and Artesian Flows Due to the wilderness character of the basin, there is no data on the location of springs, wells, and artesian flows. Ho!flever, winter aufeis bui 1 dups have been observed between Vee Canyon and Fog Creek, i ndi cati ng the presence of ground water discharges. Ground water is the main source of flow during winter months, when precipitation falls as snow and there is no glacial melt. It is believed that much of this water comes from unconfined aquifers (Freethey and Scully, 1980). · · (d) Hydraulic Connection of Mainstem and Sloughs Ground water studies in respresentative sloughs downstream of Devil Canyon indicate that there is a hydraulic connection between the mai nstem Susitna River and the sloughs. These sloughs are used by salmonid species for spa\ming and hence are important to the fisheries. Ground water observation wells indicate that the upwelling in the sloughs, which is necessary for egg incubation, is caused by ground water flow from the uplands and from the mai nstem Susitna. The higher permeabilitY of the valley bottom . sediments (sand-gravel-cobble-alluvium) compared with the till mantle and bedrock of the valley sides indicates that the mainstem Susitna River is the major source of ground water inflow in the sloughs. Preliminary estimates of the travel time of the ground water from the mai nstem to the sloughs indicate a time on the order of six months. 2.5-Existing Lakes, Reservoirs, and Streams (a) Lakes and Reservoirs There are no existing reservoirs on the Susitna River or on any of the tributaries flowing into either Watana or Devil Canyon Reser- voirs. No 1 akes downstream of the reservoirs are expected to realize any impact from project construction, impoundment, or operation. A few lakes at and upstream of the damsites, however, will be affected by the project. · The annual maximum pool elevation of 2190 feet in the Watana Reservoir will inundate several lakes, none of which are named on USGS topographic quadrangle maps. Most of these are small tundra lakes and are located along the Susitna between RM 191 and RM 197 near the mouth of Watana Creek. There are 27 1 akes 1 ess than 5 acres in surface area, one between 5 and 10 acres,. and one relatively large one of 63 acres, all on the north side of the river. In addition, a small lake (less than 5 acres) ·lies on the south shore of the Susitna at RM 195.5 and another of about 10 acres in area lies on the north side of the river at RM 204. Most of these lakes appear to be simply perched, but five of them are connected by small streams to Watana Creek or to the Susitna River itself. · E-2-24 - - - - - - -' ' - - ,... (b) A small lake (2.5 acres) lies on the south abutment near the Devil Canyon damsite, at RM 151.3, and at about elevation 1400 feet. No other lakes exist within the proposed Devil Canyon Reservoir. Streams ,· Several streams in each reservoil· will. be completely or partially inundated by the raJsed water levels during project filling and operation. The streams appearing on the 1;63,360 sclae USGS quadrang 1 e maps are 1 i sted by reservoir in Tab 1 es E. 2.10 and E.2.11. Listed in the tables are map name of each stream, river mile locations of the mouth, existing elevation of the stream mouths, the average stream gradient, the number of miles of stream to be inundated. Annual maximum reservoir elevations of 2190 feet and 1455 feet were used for these determinations for the Watana and Devil Canyon pools, respectively. There is a small slough with two small ponds on it at RM 212, four miles upstream from the mouth of Jay Creek. This slough, which is at approximate 1 y e 1 ev at ion 1750, wi 11 be completely inundated by the Watana Reservoir. Similarly, there are five sloughs (at RM 180.1, 174.0, 173.4, 172.1, and 169.5) which will be totally inun- dated by the Devil Canyon Reservoir. Aside from the streams to be inundated by the two project ·impound- ments, there are several tributaries downstream of the project which may be affected by changes in the Susitna River flow regime. Since post-project summer stages in the Susitna will be several feet 1 ower than pre-project 1 evel s, some of the creeks may either degrade to the lower elevation or remain perched above the river. Analysis was done on 19 streams between Devil Canyon and Talkeenta which were determined to be important for fishery reasons or for maintenance of existing crossings by the Alaska Railroad (R&M 1982). These streams are 1 i sted in Table E. 2.12, with their river mile locations and reason for concern. 2.6 -Existing Instream Flow Uses In stream flow uses are uses made of water in the stream channel as opposed to withdrawing water from the stream for use. Instream flow used include hydroelectric power generation; commercial or recreational navigation; waste load assimilation; downstream water rights; water requirements for riparian vegetation, fish and wildlife habitat; and recreation; freshwater recruitment to estuaries; and water required to maintain desirable characteristics of the river itself. Existing instream flow uses on the Susitna River include all these uses except hydroelectric power operation. {a) Downstream Water Rights The 18 different areas in the Susitna River Basin investigated for water rights are shown in Figure E.2. 73 (Dwight, 1981). Table E. 2.13 indicates the total amount of surface water and ground water appropriated within each area. The only significant uses of surface water in the Susitna River Basin occur in the headwaters of the Kahiltna and Willow Creek township grids where placer E-2-25 -------··-···- mining operations take place on. a seasonal basis. No surface water withdrawals from the Susitna River are on file with the Alaska Department of Natural Resources (DNR). Ground water appro- priations on file with DNR for the mainstem Susitna River corridor are minimal, both in terms of number of users and the amount of water being withdrawn. An analysis of topographic maps and overlays showing the specific location of each recorded appropriation within the mainstem Susitna River corridor indicated that neither the surface water diversions from small tributaries nor the groundwater withdrawals fromshallow wells will be adversely affected by the proposed Susitna Hydroelectric project (Dwight 1981). Hence, no further discussion on water rights is presented. (b) Fishery Resources The Susitna River supports populations of both anadromous and resident fish. Important commercial, recreational, and subsis- tence species include pink, chum, coho, sockeye and chinook salmon, eulachon, rainbow trout, and Arctic grayling. Instream flows presently provide for fish passage, spawning, incubation, rearing, overwintering, and outmigration. These activities are correlated to the natural hydrograph. Salmon spawn on the receeding 1 imb of the hydrograph, the eggs incubate through the low-flow period and fry emergence occurs on the ascending limb of the hyclrograph. Rainbow trout and grayling spawn during the high flows of the breakup period with embryo development occurring . during the early summer. Alteration of the natural flow regime during reservoir filling and project operation will likely result in both detrimental and beneficial effects on the fishery resources of the Susitna River (see Chapter 3). (c) Navigation and Transportation Navigation and transportation use of the Susitna River presently consists of boat-ing for recreation sport fishing, hunting, and some transportation of goods. The reach from the headwaters of the Susitna River to the Devil Canyon damsite has experienced limited use, primari 1 y related to hunters and fishers 1 access to the Tyone River area after launching at the Denali Highway. Some recreational kayaking, canoeing, and rafting has also taken place downstream from the Denali Highway Bridge, generally stopping near Stephan Lake or some other points above the rapids at Devil Creek~ Steep rapids near Devil Creek and at the Devil Canyon dam site are barriers to most navigation, though a very small number of kay- akers have successfully traveled through the Devil Canyon rapids in recent years. There have been severa1 unsuccessful attempts to penetrate the canyon, both going upstream and downstream, in a powerboat and in kayaks. E-2-26 - - - - - - -' ' - (d) Below Devil Canyon, the river is used for access to salmon fishing at several sites as far upstream as Portage Creek. This is under- taken by private boat-owners and by anglers using commercial boat operators. In either case, most of the boat-launching is done at Talkeetna. Commercial operators from Talkeetna also cater to sightseeing tourists, who travel upriver to view the diversified terrain and wildlife. There is recreational boating in this reach, frequently by kay akers or canoeists floating downriver to Talkeetna from the railroad access point at Gold Creek. Access to the Susitna downstream of Talkeetna is obtai ned at Talkeetna, from a boat-launching site at Susitna Landing near Kashwitna, at several of the minor tributaries between Talkeetna and Cook Inlet, and from Cook Inlet. Other primary tributaries accessible by road are Willow.Creek, Sheep Creek, and Montana Creek. Virtually this entire reach of the Susitna is navigable under most flow conditions although abundant floating debris during extreme high water and occasional shallow areas during low water make navigation treacherous at times. Identified restrictions of open-\'later navigation over the full 1 ength of the river are tabula ted in Tab 1 e E. 2.14. Under the existing flow regime, the ice on the river breaks up and the river becomes ice-free for navigation in mid to late May. Flows typically remain high from that time through the summer until later September or early October, when freezing begins. The onset of river freezing causes discharge of significant frazil ice for several days in an initial surge, which hinders boat opera- tion, but this is often followed by a frazil-free period of 1 to 2 weeks ltlhen navigation is again feasible. The next sequence of ·frazil generation generally leads into continuous freezing of the river, prohibiting open-water navigation until after the next spring breakup. The Susitna is used by several modes of non-boat transportation at various times of the year. Fixed-wing aircraft on floats make use of the river for landings and take-offs during the open water sea- son. These are primarily at locations in the lower 50 miles above the mouth. Floatplane access also occurs on occasion within the middle and upper Susitna reaches. After the river ice cover has solidly formed in the .fall, the river is used extensively for transportation access by ground methods in several areas. Snow machines and dogsleds are commonly used below Talkeetna; the Iditarod Trail crosses the river near the Yentna River confluence and is used for an annual dogsled race in February. Occasional crossings are also made by automobiles and ski, primarily near Talkeetna and near the mouth. Recreation Information on the recreation uses on the Susitna River are pre- sented in Chapter 7. E-2-27 (e) Riparian Vegetation and Wildlife Habitat Wetlands cover large portions of the Susitna River Basin, includ- ing riparian zones along the mainstem Susitna, sloughs, and tribu- tary streams. Wetlands are biologically important because they generally support a greater diversity of wildlife species per unit area than most other habitat types in Alaska. In addition, ripar- ian wetlands provide winter browse for moose and, during severe w·inters, can be a critical survival factor for this species. They also help to maintain water quality throughout regional water- sheds. Further information on riparian wetlands and wildlife hab- itat can be found in Chapter 3. (f) Waste Assimilative Capacity Review of the Alaska Department of Environmental Conservation doc- ument entitled 11 lnventory of Water Pollution Sources and Manage- ment Actions, Maps and Tablesu {1978) indicates that the primary sources of pollution to the Susitna River watershed are placer mining operations. Approximately 350 sites were identified although many of these claims are inactive. As the result of these operations, 1 arge amounts of suspended sediments are intro- duced into the watershed. However, no biochemical oxygen demand (BOO) is placed on the system and therefore, the waste ass imil a- tive capacity remains unaffected by these m·ining activities. / As for BOD discharges in the watershed, the inventory did identify one municipal discharge in Talkeetna, two industrial wastewater discharges at Curry and Talkeetna, and three solid waste dumps at Talkeetna, Sunshine, and Peters Creek. No volumes are avail able for these pollution sources. During personal communication (1982) with Joe LeBeau of the Alaska Department of Environmental Conservation (DEC) it was noted that no new wastewater discharges of any significance have developed since the 1978 report. Further, he noted that the sources that do exist are believed to be insignificant. Mr. Robert Flint of the DEC i nd ic a ted that, in the absence of reg- ulated flows and significant h'astewater discharges, the DEC has not estab 1 ished minimum flow requirements necessary for the main- tenance of the waste assimilative capacity of the river (personal communication, 1982). {g) Freshwater Recruitment to Estuaries The Susitna River is the chief contributor of fresh\'l"ater to Cook Inlet and as such has a major influence on the salinity of Cook Inlet. The high summer freshwater flows cause a reduction in Cook Inlet salinities. During winter flows the reduced flows per- mit the more saline water to move up Cook Inlet from the ocean. Using a computer model for the Cook In1et~ Resource Management E-2-28 - - - ~' .... - - -I "I ..,.. .· :· i - -' Associates (RMA, 1982) predicted a seasonal salinity variation near the mouth of the Susitna River of 15 parts per thousand (ppt). In the central part of the inlet, salinity varies seasonally by about 5 ppt. Salinity measurements were taken at the mouth of the Susitna River in August 1982 to determine if and to what extent saltwater in- truded upstream. No saltwater intrusion was detected. Flow was approximately 100,000 cfs at Susitna Station at the time the meas- urements were made. Additional salinity measurements will be made during the 1982-83 winter season to determine if salt water pene- tration occurs upstream of the mouth of the river during low flow periods. 2. 7 -Access P 1 an (a) Flows The streams crossed by the access road are typical of the sub- arctic, snow-dominated flow regime, in which a. snownelt flood in spring is followed by generally low flow through the summer, punctuated by periodic rainstorm floods. During October-April, precipitation falls as snow and remains on the ground. The annual low flow occurs during this period, and is almost completely base flow. Streamflow records for these small streams are sparse. Conse- quently, regression equations developed by the U.S. Geological Survey (Freethey and Scully, 1980) have been utilized to estimate the 30-day 1 ow flows for recurrence intervals of 2, lO, and 20 years, and the peak flows for recurrence intervals of 2, 10, 25, and 50 years. These flows are tabulated in Tab 1 e E. 2.15 for three segments of the access route: (1) Denali Highway to Watana Camp; (2) Watana Camp to Devil Canyon Camp; and (3) Devil Canyon to Gold Creek. Only named streams are presented . (b) Water Quality At present very little water quality data is available for the water resources in the vicinity of the proposed access routes. 2.8 -Transmission Corridor The transmission corridor consists of four segments: the Anchorage- Willow line, the Fairbanks-Healy line, the Willow-Healy Intertie, and the Gold Creek-Watana 1 ine. The first two (from Anchorage and Fair- banks) have existing facilities, but they will be upgraded before Watana comes on 1 ine. The intertie is currently being constructed under another contract. The 1 ine between the dam and the intert ie has yet to be designed, sited, or constructed. E-2-29 I !- (a) Flows Numerous waterbodies in each of the four sections will be crossed by the transmission· 1 ine. Most of these are small creeks in remote areas of the reg ion, but each segment has some major cros- sings. Data are very 1 imited on the small streams, both v1ith respect to water quantity and water quality. Most of the major crossings~. however, have been gaged at some point along their length by the USGS. Major stream crossings are identified below. Pertinent gage records are summarized in Table £.2.16. The Anchorage-Willow segment will cross Knik Arm of Cook Inlet with a submarine cable. Further north, major stream crossings include the Little Susitna River and Willow Creek, both of which have been gaged. The Fairbanks-Healy .1 ine wi 11 make two crossings of the Nenana River and one of the Tanana River, both large rivers and gaged. The intert ie route between Wi 11 ow and Healy will cross several dozen small creeks, many of which are unnamed. Major streams, include the Talkeetna, Susitna, and Indian Rivers; the East Fork and Middle Fork of the Chulitna River; the Nenana River; Yanert Fork of the Nenana; and Healy Creek. The final leg of the transmission corridor~ from Gold Creek to Watana Dam, will cross only one major river; the Susitna. Two smaller but sizeable tributaries are Devil Creek and Tsusena Creek~ neither of whick/nave been gaged. (b) Water Quality At present, essentially no data is available for those sections of streams~ rivers, and lakes that exist in close proximity to the·· proposed transmission corridors. E-2-30 - ~I - ...... ·~ -~ I 3 -PROJECT IMPACT ON WATER QUALITY AND QUANTITY 3.1 -Proposed Project Reservoirs (a) (b) Watana Reservoir Characteristics · The Watana Reservoir will be operated at a normal maximum water level of 2185 feet above mean sea level, but will be allowed to surcharge to 2190 feet in late August during wet years. Average annual drawdown will be 105 feet with the maximum drawdown equal- ling 120 feet. During extreme flood events the reservoir will rise to 2193.3 for the 1 in 10,000 year flood and 2200.5 feet for the probable maximum flood respectively. At elevation 2185, the reservoir will have a surface area of 38,000 acres and a total volume of 9.47 million acre-feet. Max- imum depth will be 735 feet and the corresponding mean depth will be 250 feet. The reservoir will have a retention time of 1.65 years. The shoreline length will be 183 miles. Within the Watana reservoir area the substrate classification varies great- ly. It consists predominantly of glacial, colluvial, and fluvial unconsolidated sediments and several bedrock 1 ithol ogies. Many of these deposits are frozen. · . Devil Canyon Reservoir Characteristics Devil Canyon reservoir will be operated at a normal maximum oper- ating level of .1455 feet above mean sea level. Average· annual drawdown will be 28 feet with the maximum drawdown equalling 50 feet. At elevation 1455 the reservo.ir has a surface area of 7800 acres and a volume of 1.09 million acre-feet. The maximum depth will be 565 feet and the mean depth 140 feet. The reservoir will have a retention time of 2.0 months. Shoreline length will total 76 miles. Materials forming the walls and floors of the reser- voir area are composed predominantly of bedrock and glacial, colluvial, and fluvial materials.· 3.2 -Watana Development For details of the physical features Of the Watana development, refer to Section 1 of Exhibit A. (a) Watana Construction (i) Flows During construction of the diversions tunnel, the flow of ·the mainstem Susitna will be unaffected except during spring flood runoff. Upon completion of the diversion facilities in the autumn of 1986, closure of the upstream cofferdam will be completed and flow will be diverted through the lower diversion tunnel without any interruption in flow. Although flow will not be interrupted, a one mile E-2-31 section of the Susitna River will be dewatered. significant impacts should result from this action. No Flows, velocities, and associated water levels upstream of the proposed Watana damsite will be unaffected during con- struction except for approximately one half mile upstream of the upstream cofferdam during winter and two miles up- .stream during summer flood f1ows. During winter, ponding to elevation 1470 feet will be required to form a stable ice cover. However, the vo-lume of water contained in this pond is insignificant relative to the total riv.er flow. During the summer, the diversion intake gates will be fully opened to pass the natura 1 flows resulting in a run-of- river operation. All flows up to approximately the mean annual flood will be passed through the lower diversion tunnel. Average velocities through the diversion tunnel ( will be 18, and 35 feet per second~(f/s) at discharges of 20,000, and 40,000 cfs respectively •. · The mean annual flood of 40,800 cfs will cause higher th n natural water levels \._f_gr about sever a 1 miles upstream ,6f the cofferdam. The water 1 eve1 wi 11 rise at the upstream cofferdam from a natural water level of 1,468 feet to 1,520 feet. Two miles upstream, the water level will be about 4 feet higher than the natural water level during the mean annual flood. The two diversion tunnels are designed to pass the 1 in 50 year return period flood of 87,000 cfs with a maximum head- pond elevation of 1,536 feet. For flows up to the 1 in 50 year flood event, water levels and velocities downstream of the diversion tunnels wn 1 be the same as preproject 1 evel s. (ii) Effects on Water Quality -Water Temperature Since the operation of the diversion structure will essentially be run-of-river, no impact on the temperature regime will occur downstream of the tunnel exit. A small amount of pending will occur early in the freeze-up stage to enhance the formation of a stable ice cover upstream of the tunnel intake. This will not have a noticeable effect downstream. -Ice During freeze-up, the formation of an upstream stable ice cover by use of an ice-boom and some pending to reduce approach velocities, will serve to protect the diversion works and maintain its flow capacity. The early forma- tion of the cover at this point will cause a more rapid E-2-32 ~, - - - ~. - ice front progression upstream of the damsite. · The ice formed in the upper reach, which normally feeds the downstream ice· growth, will no longer be available. However the major contributer of frazil ice will be the rapids through Devil Canyon as it now is. Hence, no appreciable impact on ice formation downstream of Watana will occur due to the diversion scheme. The ice cover upstream of the damsite wi 11 thermally decay in place, since its movement downstream would be restricted by the diversion· structure. Downstream of Devil Canyon the vo 1 ume of ice in the cover will be essentially the same as the baseline conditions and breakup would 1 ikely be similar to natural occurrences. -Suspended Sediments/Turbidity/Vertical Illumination During construction, suspended sediment concentrations and turbidity levels are expected to increase within the impoundment area, and for some distance downstream. This will result from the necessary construction activities within and immediately adjacent to the river, including: dredging and excavation of grave 1 from borrow areas, ex- cavation of diversion tunnels, placement of cofferdams, vegetative clearing, blasting, gravel processing and de- watering. The location and subsequent excavation of the material from proposed borrow sites will create the greatest potential for suspended sediment and turbidity problems. The proposed borrow sites, identified in Figure E2. 74, are tentatively located in the river floodplain both upstream and downstream of the dam site. However, except for the material for the upstream cofferdam, the lower borrow material will be obtained from sites D and E. Material for the core of the main dam will be obtained from site D (10,000,000 yardst. Material for the filters and shell of the main dam will be obtai ned from site E {52,000,000 yards). Borrow excavation will take place during the summer months when suspended sediment and turbidity values in the mainstem of the river are already quite high. As a result, incremental imp·acts during the summer should not be significant. Stockpiling of gravel is expected to alleviate the need for excavation during the winter, when the impact on overwintering fish due to· changes in suspended load would be greatest. As a result of the proposed scheduling of activities, impacts will be minimized. However, it is inevitable that there will be some increases in suspended sediments and turbidity during winter, but these should be short-term and 1 ocal ized. Downstream, turbidity and suspended sediment levels should remain essentially the same as baseline ·conditions. E-2-33 Decreases in summer and winter vertical i1lumination are expected to be commensurate with any increased suspended sediment concentrations. Si nee summer flows vii 11 be passed through the diversion tunnel with no im~oundment, no settling of suspended sed- iments is expected to occur. The insignificant headpond that will be maintained during winter is not expected to affect the very 1 ow suspended sediment and turbidity 1 evel s present during the winter season. -Metals Slight increases in the concentration of trace metals could occur during construction when disturbances to soils and rock occur on the shoreline and in the river- bed. Such increases are expected to be below detection limits and thus would not indicate a change from baseline conditions described in Section 2.3 (a) (xiii). -Contaminat1on by Petroleum Products Accidental spillage and leakage of petroleum products can contaminate water during construction. Lack of main- tenance and service to vehicles could increase the leak- age of fuel, lubricating oils, hydraulic fluid, anti- freeze, etc. In addition, poor storage and handling techniques caul d 1 ead to accident a 1 spi 11 s. Given the dynamic nature of the river, the contaminated water would be quickly diluted; however the potential for such sit- uations will be minimized. All state and federal reg- u1 at ions governing the prevention and reel amat ion of accidental spills will be adhered to. -Concrete Contamination Construction of the Watana project will create a poten- tial for concrete contamination of the Susitna River. The wastewater associated with the batching of concrete, if directly discharged to the river, could seriously de- grade downstream water quality and result in substantial mortality of fish. However, this potential problem should not occur since the wastewater will be neutralized and sett 1 i ng ponds ~~~ill be emp 1 oyed to a 11 ow the concrete contaminants to sett 1 e prior to the discharge of the wastewater to the river. -Other No additional water quality impacts are anticipated. E-2-34 - -~. - ..... .... - - - (iii) Effects on Groundwater Conditions (iv) No impacts on groundwater wi 11 occur because of construc- tion, either in the impoundment area or downstream other than in the localized area of the project. Impact on Lakes and Streams in Impoundment Area There will be minor impacts on lakes and streams in the impoundment area due to excavation of borrow material. Also~ faci 1 it i es wi11 be constructed to house and support construction personnel and their families. The construction, operation and maintenance of these facilities is expected to impact the Tsusena and Deadman Creek drainage basins and some of the small lakes located between the two creeks near the dam site. For a complete discussion of these impacts refer to the discussion on Facilities in paragraph (vi) below. (V) Instream Flow Uses For all reaches of the Susitna River except for the immedi- ate vicinity of the Watana damsite, there will be virtually no impact on navigation, transportation, recreation, fish- eries, riparian vegetation, wildlife habitat, waste load assimilation or the freshwater recruitment to Cook Inlet for flows less than the 1 in 50 year flood event. -Navigation and Transportation Since all flow will be diverted, there will only be an impact on navigation and transportation in the immediate vicinity of Watana dam and the diversion tunnel. The cofferdams will form an obstacle to navigation which will be difficult to circumvent. However, since this stretch of river has very 1 imited use due to the heavy rapids upstream and downstream of the site~ impact will be minimal. -Fisheries During' winter, the djversion gate will be partially closed to maintain a headpond with a water surface eleva- tion of 1,470 feet. This will cause velocities greater than 20 feet per second at the gate intake. This coup- led with the 50 foot depth at the intake will impact fisheries. The impacts associated with the winter diver- sion are discussed in Chapter 3.2.3. During summer, the diversion gates will be fully opened. This will permit downstream fish movement during low flows of about 10,000 cfs (equivalent velocity 9 feet per E-2-35 second (fps)). Higher tunnel velocities will lead to fish mortality. The impacts associated with summer tunnel velocities are discussed in Chapter 3.2.3. -Riparian Vegetation Existing shore 1 i ne vegetation upstream of the cofferdam will be inundated approximately· 50 feet to elevation 1, 520 during flood events. However. the flooding wi 11 be confined to a two mile river section upstream of the cof- ferdam, with the depth of flooding 1 esseni ng with dis- tance upstream. Si nee the flooding wi 11 be infrequent and temporary in nature, and the flooded lands are within the proposed reservoir, the impact is not considered significant. Further information on the impacts to riparian vegetation can be found in Chapter 3. (vi) Facilities The construction of the Hat ana power project will require the construction, operation and maintenance of support facilties capable of providing the basic needs for a maxi- mum population of 4,720 people (3,600 in the construction camp and 1,120 in the village) (Acres, 1982).-The facili- ties, including roads, buildings. utilities, stores, rec- reation facilities, airports, etc •• will be constructed in stages during the first three years (1985-1987) of the proposed ten-year construction peri ad. The camp and vil- lage wi 11 be 1 ocated approximately 2. 5 miles northeast of the Watana damsite, between Deadman and Tsusena Creeks. The location and layout of the camp and vi1lage facilities are presented in Plates 34, 35, and 36 of Exhibit F. -Water Supply Nearby Tsusena Creek will be utilized as the major source of water for the community (Plate 34). In addition, wells will be drilled in the Tsusena Creek alluvium as a backup water supply. During construction, the required capacity of the \'later treatment plant has been estimated at 1,000,000 gallons per day, or 700 gallons per minute ( 1.5 cfs) (Acres, 1982). Using the USGS regression equation described in Table E2.15, 30-day minimum flo~tts (cfs), with recurrence intervals of 20 years were estimated for Tsusena Creek near the water supply intake. The low flow wa& estimated to be 17 cfs for the approximate 126 square mi 1 es of drainage basin. As a result, no significant adverse- impacts are anticipated from the maximum water supply withdrawal of 1.5 cfs. Further, a withdrawal of this E-2-36 - ..... - - - - - magnitude should not· occur during the low flow winter months since construction personnel will be significantly less than during summer. The water supply will be treated by chemical addition,. flocculation, filtration and disinfection prior to its use. Disenfection should probably be \'lith ozone to avoid having to dechlorinate. In addition, the water will be demineralized and aerated, if necessary. -Wastewater Treatment A secondary waste water 'treatment faci 1 ity wi 11 treat all waste water prior to its discharge into Deadman Creek (Plate 34). Treatment will reduce the BOD and total suspended solids (TSS) concentrations to levels acceptable to the Alaska Department of Environmental Conservation. The levels are 1 ikely to be 30 mg/1 BOD and 30 mg/1 TSS. The maximum volume of effluent, 1 million gallons per day or 1.5 cfs, will be discharged to Deadman Creek which has a low flow of 27 cfs (see below). This will provide a dilution factor of about 17, thereby reducing BOD and TSS concentrations to about 2 mg/1 after complete mixing under the \'IOrst case flow conditions (maximum effluent and low flow in Deadman Creek). Mixing will occur rapidly in the creek because of turbulent conditions. The effluent is not expected to cause any degredations of water quality in the 1 1/2 mile section of Deadman Creek behJeen the waste water discharge point and the creek • s confluence with the Susitna River. Furthermore, no water quality problems are anticipated within the impoundment area or downstream on the Susitna River as a result of the input of this' treated effluent. Using the USGS regression analysis, the one in 20 year, 30-day low flow for Deadman Creek at the confluence with the Susitna, was estimated at 27 cfs. Flow at the point of discharge which is less than two miles upstream, are not expected to differ significantly. Construction of the waste water treatment faci 1 ity is expected to be completed in the first 12 months of the Watana construction schedule. Prior to its operation, a 11 waste wi 11 be stored in a 1 a goon system for treatment at a 1 ater date. No raw sewage wi 11 be discharged to any water body. The applicant will obtain all the necessary DEC, EPA, DNR, and PHS permits for the water supply and wastewater discharge facilities~ E-2-37 -Construction, Maintenance and Operation Construction of the Watana camp, village, airstrips, etc~ will cause impacts to water quality similar to many of those occuring from dam construction. Increases in sed- imentation and turbidity levels are anticipated in the local drainage basns. (i.e., Tsusena and Deadman Creeks). Even with extensive safety controls, accidental spill age and leakage of petroleum products could occur creating localized contamination within the watershed. (b) Impoundment of Watana Reservoir (i) Reservoir Filling Criteria The filling of the Watana reservoir is scheduled to com- mence in May 1991. -Minimum downstream target flows In the selection of minimum target flows, fishery con- cerns and economics were the two contro11 i ng factors. Although not unimportant in the over a 11 impact assess- ment, other i nstream flow uses, were determined not to have a significant influence on the selection of minimum downstream target flows. However, i nstream uses such as navigation and transportation, recreation, and waste load assimilation are closely related to the instream flow requirements of the fishery resources. Minimum downstream target flows \·till be provided at Gold Creek since Gold Creek flows are judged to be representa- tive of the Talkeetna to Devil Canyon reach where down- stream impacts will be greatest. The mini"mum target flows at Gold Creek will be attained by releasing that flow necessary from the Hatana impoundment, which when added to the flow contribution from the intervening drainage area between Watana and Gold Creek, will equal the minimum Gold Creek target flow. The a~b.sol,4te minimum flow release at Watana will be 1,000 ~cfs ~{)r natural flows, whichever is less. During flll+rl§l;-·fiows at Gold Creek will be monitored and the flow at Watana adjusted as necessary to provide the required Gold Creek flow. Table [.2.17 ·illustrates the targeted minimum Gold Creek flows. The minimum downstream flow of 1000 cfs from November through April is some\;~hat lower than the average winter flow at Gold Creek. l From May to the last week of July, the target flow wi 11) \ ~e. increased to 6, 000 cfs to all ow for ma i nstem fishery . · ~ovement. During June, it may be desirable to spike the ffows to trigger the outmigration of salmon fry from thet sloughs. (Schmidt, 1982 personal communication). It is believed that the outmigration is triggered by a combina- tion of stage, discharge and temperature. Trihey (1982) has observed that the fry outmi grate during the falling 1 imb of the spring flood hydrograph. E-2-38 ----------------~----------- - - ( i i) ~-, The 6,000 cfs Gold Creek flow will provide a minimum of 2 feet of river stage for mainstem fishery movement at all 65 surveyed cross sections between Talkeetna and Devil Canyon. Figure E2. 75 i 11 ustrates computed water surface elevations for various discharges at cross section 32 1 ocated near Sherman (RM 130). (Accuracy is + 1 foot). This cross section is believed to be the shallowest in the Talkeetna to Devil Canyon reach. The estimated water surface elevation for a discharge of 6000 cfs indicates that the depth is greater than 2 feet. During the last 5 days of July, flows will be increased from 6,000 cfs to 12,000 cfs in increments of approxi- mately 1,500 cfs per day. Flows will be maintained at ,12,000 cfs from August 1 through mid-September to coin- cide approximately with the sockeye and chum spawning season in the sloughs upstream of Talkeetna. Adverse impacts to fish resulting from this flow regime are discussed in Chapter 3.2.3. After 15 September, flows will be reduced to 6,000 cfs in daily increments of 1,500 cfs and then held constant un- t i 1 October when they wi 11 be further reduced to 2,000 cfs. In November, the flow will be lowered to 1,000 cfs. -Flood Flows Taking into account the 30,000 cfs discharge capability of the low level outlet, sufficient storage will be made available during the filling sequence such that f'lood volumes for all floods up to the 250 year recurrence in- terval flood can be temporarily stored in the reservoir without endangering the main dam. Whenever this storage criteria is violated, discharge from the Watana reservoir will be increased up to the maximum capacity of the out- let to lower the reservoir level behind the dam. Reservoir Filling Schedule and Impact on Flows Using the reservoir filling criteria, three simulated reservoir filling sequences were examined to determine the likely filling sequence and probable deviations. Asap- proximately three years will be required to bring the res- ervoir to its normal operating level, three year running averages of the total annual flow volume at Gold Creek-were computed. The probability of occurrence for each of the three year average values was then determined. Using the 10, 50, and 90 percent exceedence probability val umes and E-2-39 the long term average monthly Gold Creek flow distribution, Gal d Creek flow hydrographs were synthesized for each probability. An identical process \'las used to synthesize the 10, 50, and 90 perc~nt probability volumes and flow distributions at Watana. The intermediate flow contribution was taken as the difference between the Watana and ~old Creek monthly flows. Then using the downstream flow criteria and the flow values at Watana and Gold Creek, the fiiling sequence for th~ thr~e probabiiities was determined by repeating the annual flow sequence until the reservoir was filled. The reservoir water levels and the Gold Creek flows for the three fi 11 i ng cases considered are i 11 ustrated in Figure E2.76. Under average conditions the reservoir would fill sufficiently by autumn 1992 to allow testing and com- missioning of the units to commence. However, the reser- voir would not be filled to its normal operating level until the following summer. There is a 10 percent chance that the reservoir would not be sufficently full to permit the start of testing and commissioning until late spring 1993. Only about one month is saved over the average filling time if a wet sequence occurs. This is because the flood protection criteria is violated and flow must be by- passed rather than stored. The Watana discharges for the high (10 percent), mean (50 percent) and low (90 percent) flow cases considered are compared to the Watana inflow in Table E2.18. For the average hydrologic case, pre-project discharge for the May-October period is reduced by approximately 60 percent during the filling period. However, from November through April there is little difference. For the Devil Canyon to Talkeetna reach, Gold Creek flows are considered representative. Monthly pre-project and filling flows at Gold Creek for the wet, (10 percent), mean (50 percent), and dry (90 percent) sequences are i 11 us- trated in Table E2.19. Percentage summer and winter flow changes are simi 1 ar to those at Watana but are somewhat reduced because of additional tributary inflow. For the mean case, August monthly flow at Gold Creek is reduced by 45 percent (21,900 cfs to 12,000 cfs) when the reservoir is capable of storing all flow less the downstream flow re- quirement. Flows will be altered in the Talkeetna to Cook Inlet reach, but because of significant tributary contributions the impact on summer flows will be greatly reduced with dis- tance downstream. Table E2.20 is a comparison of mean pre- project monthly flows and monthly flows during reservoir filling at Sunshine and Susitna Station. Pre-project flows are based on the 1 ong-term average ratio between the respective stations and Gold Creek. Filling flows are pre-project fl ovts reduced by-the flow stored in the reservoir. E-2-40 """' - - -Floods The reservoir filling criteria, dictates that available storage volume in the reservoir. must provide protection for all floods up to the 250 year recurrence interval flood. Thus, the reservoir must be capable of storing a 11 flood inflow except for the flow which can be dis- charged through the outlet facilities during the flood event. The maximum Watana discharge of the outlet facil- ities is 30,000 cfs. A maximum flow at Watana at 30,000 cfs represents a substantial flood peak reduction which will reduce downstream flood peaks substantially as far downstream as Talkeetna. For example, the once in fifty year flood at Gold Creek would be reduced from 106~000 cfs to 49,000 cfs. After the flood event, the outlet facility will continue to discharge at its maximum capacity until the storage volume criteria is reestablished. This will cause the flood duration to be extended beyond its normal duration although at a reduced flow as noted above. The flood frequency curve for Watana during reservoir filling is illustrated in Figure E.2.77. -Flow Variability The variability of flow in the Watana to Talkeetna reach wi 11 be altered. Under natural conditions substantial change in flows can occur daily. This flow variability will be reduced during filling. Using August, 1958 as a example, Figure E.2. 78 shows the daily flow variation that would occur. The average monthly flow of 22,540 cfs during August, 1958 yields a value close to the long term average monthly discharge of 22,000 cfs. Superimposed on Figure E.2. 78 are the flow variations that could occur under filling conditions with the August 1958 inflow, first, assuming that the reservoir was capable of accommodating the inflow and second, assuming that the reservoir storage criteria was violated (i.e.~ 30,000 cfs discharge at Watana). Both Gold Creek hydrographs have ·reduced flood peaks. In filling sequence 1, outflow is greater than inflow at Watana on the receeding limb of the hydrograph in order to meet the reservoir storage volume criteria. Hence during this time period, Gold Creek flows are greater than natural. In this example it was assumed that ongoing construction did not permit additional storage. In reality, the dam height will be increasing and add it i anal storage waul d be permitted, thus reducing the required outflow from Watana. This would correspondingly reduce the Gold Creek discharge. E-2-41 In filling sequence 2, Gold Creek flmv is constant at 12,000 cfs. However, at Watana, flow would be 4,350 cfs -at the peak and about 10,000 cfs when the natural Gold Creek flow drops to 12,000 cfs. Further downsteam, the variability of flow for both sequences will increase as a result of tributary inflow, but will be less than under natural conditions. (iii) River Morphology During the filling of Watana reservoir, the trapping of bed- 1 oad and suspended sediment by the reservoir will. greatly reduce the sediment transport by the Susitna River in the Watana-Talkeetna reach. Except for i so 1 ated areas, bedload movement will remain 1 i mited over this reach because of the armor layer and the low flmvs. The lack of suspended sedi- ments will significantly reduce siltation in calmer areas. The Susitna River main channel will tend to become more defined with a narrower channe 1 in this reach. The main channel river pattern will ·strive for a tighter, better de- fined meander pattern within the existing banks. A trend of channel width reduction by. encroachment of vegetation will begin, and will continue during reservoir operation. Tribu- tary streams, including Portage Creek, Indian River, Gold Creek, and Fourth of July Creek, will extend their alluvial fans into the river. Figure E.2.79 illustrates the influence of the mainstem Susitna River on the sedimentation process occurring at the mouth of the tributaries. Overflow into most of the side-channels will not occur, as high flows will be greatly reduced. The backwater effects at the mouths of side-channels and sloughs will be significantly reduced. At the Chulitna confluence, the Chulitna River is expected to expand and extend its alluvial deposits. Reduced summer flows in the Susitna River may allow the Chulitna River to extend its alluvial deposits to the east and south. However, high flo1ttS in the Chulitna River may cause rapid channel changes, inducing the main channel to migrate to the west. This would tend to relocate the deposition to the west. Downstream of the Susitna-Chul itna confluence, the pre- project mean annual bankfull flood will now have a recurrence interval of five to ten years. This will tend to decrease the frequency of occurrence of both bed material movement and, consequently, of changes in braided channel shape, form and network. A trend toward relative stabilization of the floodplain features will begin, but this would occur over a long period of time (R&M, 1982a). (iv) Effects on Water Quality Beginning with the filling of the reservoir, many of ~he physical, chemical and biological processes common to a E-2-42 ~' - - - - lentic environment should begin to appear. Some of the more important processes include sedimentation, leaching, nutrient enrichment, stratification, evaporation and ice cover. These processes are expected to interact to alter the water quality conditions associated with the natural riverine conditions that presently exist. A summary discussion of the processes and their interactions is provided in Peterson and Nichols {1982). -Water Temperature During the first summer of fi 11 i ng, the temperature in the Watana reservoir will be essentially a composite of the inflow temperature, increased somewhat by the effects of solar heating. The reservoir will fill very rapidly {to about a 400 foot depth by the end of summer) and the effects of solar heating will not penetrate to the depth at which the outlet is located. Therefore, outlet temperatures during the first summer of filling should be an average of the existing river water temperatures with some lagging with the inflow water temperatures. During fall, the reservoir will gradually cool to 4°C. Once at this temperature the low level outlet will con- tinue to discharge water at just above 4°C until the reservoir water 1 eve 1 has increased to where the fixed cone valves can be used. Downstream of the Watana development the water tempera- ture will be modified by heat exchange with the atmos- phere. The filling sequence will cover two winter peri ads and the temperature at the downstream end of Devil Canyon will reach 0°C at or about the beginning of November in the first year and toward the end of October in the second. This will have the effect of lagging_the downstream temperatures by about 5 weeks from the base- liner. Further dm..,rnstream, the 1 aggi ng in temperatures will be reduced as climatic conditions continue to in- fluence the water temperature. During the second summer of filling, outlet temperatures will be 4°C. Downstream of Watana, the water temperature will increase but, will be well below normal water temperatures. -Ice With the delay of freezing water temperatures, the entire ice formation process will occur 3-4 weeks later than for natural conditions. However, due to the lower flows the severity of jams will be diminshed and the staging due to ice wi 11 be 1 ess than presently experienced. At breakup, E-2-43 the reduced f1 ows in combination with the diminished jamming in the river, will tend to produce a less severe breakup than currently occurs. -Suspended Sediments/Turbidity/Vertical Illumination • Watana Reservoir As the reservoir beings to fi 11, ve 1 oc it i es will be re- duced and deposition of the larger suspended sediment particles will occur. Initially, all but the larger par- ticles will pass through the reservoir, but with more and more water impounded, sma11er diameter particles will settle. As the reservoir approaches normal operating levels, the percentage of particles settling will be sim- ilar to that occurring during reservoir operation. How- ever, since during filling, water will be passed through the low level outlet which is at invert elevation 1490 feet, whereas during operation it will be drawn from above elevation 2065 feet, larger particles would be expected to pass through the reservoir during fi 11 i ng than during operation (The deposition process during reservoir operation is discussed in detail in Section 3.2 {c)(iii).). During the filling process, reservoir turbidity will de- crease in conjunction with the settling of suspended sed- iments. Turbidity will be highest at the upper end of the reservoir where the Susitna River enters. Turbid interflov1s and underflows may occur during summer months, depending on the relative densities of the reservoir and river waters. Turbidity levels in the winter are ex- pected to decrease significantly from summer levels, how- ever, turbidity is likely to be greater than pre-project winter levels. Vertical illumination in the reservoir will decrease dur- ing breakup as flow begins to bring glacial silts into the reservoir. Vertical illumination during the summer will vary, depending on where the river water finds its equilibrium depth (overflow, interflow, or underflow). Data from glacially fed Eklutna Lake indicates that vertical illumination will not exceed 4 meters during the mid-summer months (Figure E.2.80). Vertical illumination will gradually increase during the autumn as glacial input decreases. During the filling process additional suspended sediments wi 1l be introduced to the reservoir by the slumping of the valley walls and continued construction activities. The s 1 umpi ng of valley walls will provide intermittent quantities of suspended sediments. Although no quantita'- tive estimates of this impact are available, it is (ln- ticipated that these impacts will be localized, of short E-2-44 - - - - -· - - - . ,.... duration~ and thus not very significant. However, slump- ; ng is expected to continue after operation of the pro-· ject begins until equilibrium is attained. Construction activities, such as the removal of timber from within the proposed impoundment area are also expected to contribute · to increased suspended sediment concentrations and tur-· bidity levels and decreased vertical illumination. Once removed, the lack of soil-stabilizing vegetative cover will likely accelerate wall slumping. However, the in- crease in suspended sediments due to valley wall slumping will be significantly less the reduction due to the sed- i mentation process and thus the river wi 11 be clearer than under natural conditions • • Watana to Talkeetna Maximum particle sizes passing through the project area downstream, wi 11 decrease from about 500 microns during pre-project conditions to about 5 microns as filling progresses. As can be observed from the particle size distribution {Figure E.2.36) this results in a retention of about 80 percent of the pre-project suspended sediment at Watana. Because of the clear water tributary inflow in the Watana to Talkeetna reach, further reduction of the suspended sediment concentration will occur as the flow moves downstream. During high tributary flow periods, additional suspended sediment will be added to the river by the tributaries. Talus slides may also contribute to the downstream suspended sediment conc.en- trations. In general, the suspended sediment concentra- tion in the Watana to Talkeetna reach will be reduced by approximately 80 percent during the summer months and slightly increased during the winter months. Downstream summer turbidity levels will be reduced to an estimated 30-50 NTU. Winter turbidity levels, although not presently quantifiable, will be increased above natural levels of near zero. Because of the reduced tur- bidity in summer, the vertical illumination \'lill be en- hanced. Winter vertical illumination will be reduced • • Talkeetna to Cook Inlet In the Talkeetna to Cook Inlet reach, the suspended sedi- ment and turbidity 1 evel s during summer wi 11 decrease s 1 i ghtly from pre-project levels~ The Chulitna River is a major sediment contributor to the Susitna with 28 per- cent of its drainage area covered by glacier. As such, it wi 11 tend to keep the suspended sediment concentra- tions high during summer. Therefore, the summer char- acter of this reach will not change significantly. E-2-45 -Dissolved Oxygen Initially, during the 3-year filling process, the reservoir D.O. levels should approximate riverine conditions. As filling progresses, some weak stratification may begin to develop. but no substantial decreases in dissolved oxygen levels are anticipated. The volume of freshwater inf1ow, the effects of wind and waves, and the location of the out- let structure at the bottom of the reservoir are expected to keep the reservoir fairly \1/ell mixed, thereby replenish- ing oxygen levels in the hypolimnion. No significant biochemical oxygen demand is anticipated. The timber in the reservoir area wi 11 be c 1 eared, thereby eliminating the associated oxygen demand that would be cre- ated by the inundation and decomposition of this vegeta- tion. Further, the chemica 1 oxygen demand {COD) in the Susitna River is quite low. COD levels measured upstream at Vee Canyon during 1980 and 1981, averaged 16 mg/1. No significant BOD loading is expected from the construc- tion camp and vi 11 age. As previously noted, a low level outlet will be utilized for discharging water. Therefore, the. 1 evel s of oxygen immediately downstream of the outlet could be slightly reduced. However, pre-project values will be established within a short distance downstream of the outlet due to reaeration enhanced by the turbulent nature of the river. -Nitrogen Supersaturation Nitrogen supersaturation of water below a dam is poss'ible in certain seasons, extending a considerab1e distance downstream. The detrimental impact of nitrogen supersatur- ation is its lethal effect on fish. If dissolved gases reach lethal levels of supersaturation, a fish kill due to gas embo 1 isms may result for miles downstream of an i m- poundment (Turkheim, 1975). Nitrogen supersaturation can be caused by passing water over a high spillway into a deep plunge pool. The factors influencing this phenomenon include the depth of the plunge pool, the height of the spill way and the amount of water being spilled. Si nee a 11 flow \'lill be passed through the low level diversion tunnel and no spilling of water w·ill occur at the i~atana damsite, this problem will not exist during fi 1 Ti ng. -Nufr i ents - Two opposing factors \'till affect nutrient concentrations during the ftlling process. First, initial inundation will likely cause an increase in nutrient concentrations. E-2-46 - - ~.· ·- - - - Second, sedimentation will strip some nutrients from the water column. The magnitude of net change in nutrient concentrations is unknown, but it is likely that nutrient concentrations wi 11 increase for at 1 east a short-term during filling. -Other No significant changes in any other water quality par- ameters are anticipated. (v) Effects on Groundwater Conditions -Mai nstem Alluvial gravels in the river and tributary bottoms vlill be inundated. No significant aquifers are known to be in the reservoir area, other than the unconfined aquifers at the relic channel and in valley bottoms. Summer releases from the reservoir during filling are dis- cussed fn Section 3.2(b)(i). As a result of the decreased summer flows, water levels will be reduced, especially above Talkeetna. This will in turn cause a reduction in groundwater levels downstream but the groundwater level changes will be confined to the river floodplain area. The groundwater table will be reduced by about 2 feet in summer near the shoreline with less change occurring with distance away from the river. A similar process will occur dm~Jnstream of Ta"lkeetna, but the changes in groundwater levels will be of less magnitude due to the decreased effect on river stages. -Impacts on Sloughs The reduced rna ins tern flows and subsequently 1 ower Susitna River water levels will reduce the water level gradient between the mainstem and the sloughs. At locations where· slough upwelling is unaffected by mainstem backwater effects, the reduced gradient will result in reduced slough upwelling rates. However, an analysis of mainstem water elevations at the decreased flow rate and the slough up- welling elevations, indicates a ~ontinued positive flow toward these upwelling areas with the exception that the intersection of the slough and the groundwater table will move downstream. Data to confirm the area 1 extent of upwelling at low flows is unavailable at this time. E-2-47 The thalweg profile in slough 9 and computed mai nstem ~·rater surface profiles in the vicinity of Slough 9 are illus- trated in Figure E.2.81. The thalweg profile taken at right angles to the mainstem flow together with the main- stem water levels show that upwelling will continue at 1 ower mai nstem flows. (The water surface profi 1 es \'thich were computed using HEC-2 are sufficiently accurate to illustrate the relationship). It should also be noted that the groundwater driving head is more in an upstream- downstream direction than in a direction perpendicular to the mainstem. This can in general be attributed to the location of most sloughs at natural bends in the river. The distance from the mai nstem at the head end of the sloughs to the mainstem at the mouth of the sloughs is usually shorter through the sloughs than along the main- stem. At the slough upwelling locations which are affected by the mai nstem backwater, the groundwater gradient between main- stem and slough is relatively unaffected by discharge until backwater effects are no 1 anger present at the upwelling 1 a cation. (As the ma i nstem water leve 1 decreases at the head end of the slough, there is a corresponding decrease in mainstem water level at the mouth of the slough where the backwater is controlled. Therefore, the gradient between the mainstem water level upstream and the backwater elevation in the slough is essentially unchanged.) Hence upwelling rates in backwater areas would remain virtually unchanged until the area is. no 1 anger affected by back- water. At that time the upwelling would behave as dis- cussed above. Under ice conditions the mainstem water levels increase, resulting in an increased head differential between main- stem and slough, and increased upwelling in the sloughs. Under reservoir filling conditions during winter, discharge will be reduced to about 1000 cfs at Gold Creek during the freeze-up period. This will result in reduced staging from pre-project ice staging levels. Hence, during winter, the mai nstem-s 1 ough water level differential wi 11 be reduced with a corresponding reduction in upwelling area. In summary~ based on available information to date, up- welling in sloughs will continue but at an equal or slight- ly reduced rate from. the natural rate. Additionally, the upper ends of some sloughs may be dewatered because of the 1 ower groundwater table associated with the decrease in mainstem water levels. (vi) Impacts on Lakes and Streams Several tundra lakes will be inundated as the reservoir approaches full. pool. The mouths of tributary streams E-2-48 - - ~ I ..... - - - entering the reservoir wi 11 be inundated for sever a 1 miles (Sec. 2.4 (b)). Bedload and suspended sediment carried by these streams will be deposited at or near the new mouths of the streams as the river mouths move upstream during the filling process. No significant impacts to Tsusena or Deadman Creeks are anticipated from their use as \'later·supply and waste recipient, respectively. (vii) Effects on Instream Flow Uses .... Fishery Resources, Riparian Vegetation, and Wildlife Habitat Impacts on fishery resources, riparian vegetation and wild- life habitat during the filling process are discussed more fully in Chapter 3. As summer flows are reduced, fish access to slough habitats will be decreased. Since temper- atures of upwelling groundwater in sloughs are expected to be unchanged and upwelling should continue at most loca- tions, though possibly at a reduced rate, impacts on the incubation of salmonid eggs are not expected to be severe. -Navigation and Transportation Once impoundment of the reservoir commences, the character of. the river immediately upstream of the dam will change from a fast-flowing river with numerous rapids to a still- \'later reservoir. The reservoir will ultimately extend 54 miles upstream, just downstream of the confluence with the Tyone River, and wi 11 inundate the major rapids at Vee Canyon when the reservoir reaches full pool. The reservoir will allow increased boat traffic to this reach of river by decreasing the navigational difficulties. The reduced summer flows released from the reservoir during filling could reduce the navigation difficulties between · Watana and Devil Canyon during the summer months. However, the lower segment· of this reach from Devil· Creek to Devil Canyon will still consist of heavy white-water rapids suit- able only for expert kayakers. Navigational difficulties between Devil Canyon and the con- fluence with the Chulitna River will be increased due to shallower water and a somewhat constricted channel. Al- though there will be sufficient depth in the river to navi- gate it, greater care will be required to avoid grounding. There will be less floating debris in this reach of the river, which will reduce the navigational danger somewhat. There will be little impact on navigation below the conflu- ence of the Chulitna River. The Susitna River is highly braided from Talkeetna to Cook Inlet with numerous channels which can change rapidly due to the high bedload movement E-2-49 and rea·dily erodible bed material. Navigation can be difficult at present and knowledge of the river is beneficia 1 at 1 0\'J f1 ows. The reduced summer f1 ows from the Sus itna River \'li 11 be somewhat compensated for by the high .flows from other tributaries .. No impacts near the existing boat access points of Sus itna Landing, Kaskwitna River or Willow Creek have been identified. Minor restrictions on navigation may occur at the upstream access to Alexander Slough, but this would occur only in low streamflow years when the other tributaries also have low flow. -Recreation Information on recreation can be found in Chapter 7. -Waste Assimilative Capacity The previously noted, reduct ions to downstream summer flows could result in a slight reduction in the waste assimila- tive capacity of the river. However, no significant impact is anticipated given the limited sources of waste loading on the river (see Section 3.2(a)(ii)). -Freshwater Recruitment to Estuaries During filling, under average flow conditions, the mean annual freshwater ·Inflov.t to Cook Inlet will be reduced by about 12 percent. This will cause a few parts per thou- sand increase in the natural salinity conditions. How- ever, the salinity change would still be within the range of normal variation. If filling were to. take place during an average hydrologic sequence, then the annual freshwater input to Cook Inlet would still be greater than the existing annual flows into Cook Inlet 15 percent of the time. During a dry flow sequence, the downstream flow require- ments at Gold Creek would be maintained. Thus, a smaller percentage of the Gold Creek flow is available for stor- age. Consequently the percent reduction in fresh water inflow into Cook In 1 et is Tess for a sequence of dry years than for average conditions. The higher Cook Inlet salinities will last only until project operation, at which time a new equilibrium wil be established as described in Section 3.2(c)(v). E-2-50 -~ - - """ (c) Watana ( i) , .... - - O~eration Flows -Project OQerati on Watana will be operated in a storage-and-release mode, such that summer flows will be captured for release in winter. Generally, the Watana reservoir wi 11 be at or near its normal maximum operating level of 2185 feet each year at the end of September. Gradually the reservoir wi 11 be drawn down to meet winter energy demand. In early May, the reservoir will reach its minimum annual level and then begin to refill from the spring melt. Flow in excess of both the downstream flow requirements and power needs wi 11 be stored during the summer until the reservoir reaches the normal maximum operating level of 2185 feet. Once the reservoir is at this elevation, flow above that required for power wi 11 be \'lasted. After the threat of significant flooding has passed in 1 ate August, the reservoir will be allowed to surcharge to 2190 feet to minimize wasting of water in late august and September. Then, at the end of September, the annual cycle will be repeated • • Minimum Downstream Target Flows During project operation, minimum Go 1 d Creek target f1 ows from May through September wi 11 be unchanged from those during reservoir impoundment except that flows from October to April will be maintained at or above 5,000 cfs. It . should be noted that these flows are minimum target flows. In reality, project operation flows will normally be greater than the targeted mini- mum flows during winter. During May, June, July and October,· operational flows will . also normally be ·greater than the minimums. The late July, August, and September flows wi 11 probably coincide very closely with the minimum requirements. The minimum target flows during operation are shown in Table E.2.17. If during summer, the natural flows fall below the GQld Creek minimum target, then these flows will be augment- ed to maintain the downstream flow requirement • • Monthly Energy Simulations A monthly energy simulation program was run using the 32 years of Watana synthesized flow data given in Table E2. 2 except that the extreme drought. (recurrence inter- val greater than one in 500 years) which occurred in water year 1969, dominated the analysis and was there- fore modified to reflect a drought with recurrence interval of one in 32 years for energy planning and E-2-51 drawdown optimization. Energy production was optim- ized, taking into account the reservoir operating criteria and the downstream flow requirements. The energy simulation program is discussed in Volume 4,. Appendix A of the Feasibility Study (Acres, 1982). Monthly maximum ,mini mum,and median Watana reservoir levels for the 32 year simulation are illustrated in Figure £.2.82. • Daily Operation In an effort to stabilize downstream flows. Watana will be operated as a base 1 oaded plant until Devil Canyon is completed. This will produce daily flows that are virtually constant most of the year. During summer it may be economically desirable to vary flow on a daily basis to take advantage of the flow contribution down- stream of Watana to meet the flow requirements at Gold Creek. This would yield stable flows at Gold Creek, but somewhat variable river flows between Watana and Portage Creek. -Mean Monthly and Annual Flows Monthly discharges at Watana for the 32 year period were computed using the monthly energy simulation program and are presented in Table E.2.21. The maximum, mean, and minimum flows for each month are summarized in Table E.2. 22. Pre-project flows are also presented for compari san. In general. powerhouse flows from October through April will be much greater than natural flows~ For example, in March the operational flows will be eight times greater than natural river flow. Average post pro- ject flow for May will be about 30 percent less than the natural flow. Mean daily post project flows during May will be similar for each day of the month. In contrast, existing baseline flows vary considerably from the start of the month to the end of the month due to the timing of the snowmelt. Flows during June, July, August and September will be substantially reduced, to effect reser- voir filling. Pre and post project montly flows at Gold·· Creek are listed in Tables £2.23 and E2.24. A summary is present- ed in Table £2.25. The comparison is similar to that for Watana although the pre-project/post-project percentage change is less. Further downstream at the Sunshine and Sus itna Station, gaging station pre-and-post project flow differences wil 1 become less significant. During July. average monthly flows will be reduced by eleven percent at Sus itna E-2-5? - - - - - - - - - Station. However, during the \'linter, flows will be 100 percent greater than existing conditions. Monthly pre- and post-project flows at the Sunshine and Susitna Stations are tabulated in Tables E.2.26 through E.2.29 and summarized in E2.30 and E2.31. Mean annual flow will remain the same at all stations. However, flow will be redistributed from the summer months to the \'ii nter months. -Floods • Spring Floods For the 32 years simulated, Watana reservoir had suf- ficient storage capacity to absorb all floods. The largest flood of record, June 7, 1964, had a peak dis- charge of 90,700 cfs at Gold Creek, corresponding to an annual flood recurrence interval of better than 20 years. This flood provided the largest mean monthly inflow on record at Gold Creek, 50,580 cfs and contain- ed the 1 argest flood vo 1 ume on record. However, even with this large a flood, the simulated reservoir level increased only 49 feet from elevation 2089 to elevation 2138. A further 47 feet of storage were available before reservoir spillage would have occurred. The flood volume for a May-July once in fifty year flood was determined to be 2.3 million acre feet {R&M, 1981a). This is equivalent to the storage volume con- tained between elevation 2117 and 2185, neglecting dis- charge. Si nee the maximum elevation at the beginning of June was always less than 2117 during the simula- tion, the 50 year flood volume can be stored without spill age if it occurs in June. Assuming the maximum June 30th water level in the simulation, if the flood event occurs in July, the once in fifty year flood volume can also be accommodated without exceeding Elevation 2185 if the powerhouse discharge averages 10,000 cfs. Thus, for flows up to the once in fifty year spring f1 ood event, Watana reservoir capacity is capab 1 e of totally absorbing the flood without spill age. Only for flood events greater than the once in fifty year event and after the reservoir elevation reaches 2185.5 feet, will the powerhouse and outlet facilities will be operated to match inflow up to the full operat- ing capacity of the outlet facilities and powerhouse. If inflow continues to be greater than outflow, the r~servoir will gradually rise to Elevation 2193. At that time, the main spillway gates will be opened and operated so that the outflow matches the inflow. The E-2-53 main spillway will be able to handle floods up to the once in 10,000-year event. Peak inflow for a once in 10t000-year flood will exceed outflow capacity resulting in a slight increase in water level above 2193 feet. The discharges and water levels associated with a once in 10t000-year flood are shown in Figure E.2.83. If the probable maximum flood were to occur~ the main spillway will be operated to match inflow until the capacity of the spillway is exceeded. The reservoir elevation would. rise until it reached Elevation 2200. At this elevation~ the erodable dike in the eme.rgency spillway waul d be eroded and the emergency spi 11 way would operate~ The resulting total outflow through all the discharge structures would be 15,000 cfs less than the probable maximum flood {PMF) of 326,000 cfs. The inflow and outfl O\'J hydrographs for the PMF are i 11 us- trated in Figure E.2.83. • Summer Floods For floods occurring in August and September, it is probable that the Watana reservoir could reach Eleva- tion 2185. Design considerations were therefore estab· lished to ensure that the powerhouse and outlet facili- ties will have sufficient capacity to pass the once in fifty year summer flood without operating the main spillway as the resultant nitrogen supersaturation could be detrimental to downstream fisheries. During the flood, the reservoir will be allowed to surcharge to Elevation 2193. An analysis of the once in fifty year summer flood was carried out assuming that the reservoir was at 2185 feet when the flood commenced. The inflow flood hydro- graph at Watana was derived by multiplying the mean annual flood peak at Watana by the ratio of the once in two year summer flood peak at Gold Creek to mean annual flood peak at Gold Creek to obtain the once in two year summer flood peak at Watana. This value was then multiplied by the ratio of the once in fifty year summer flood to the once in two year summer flood at Gold Creek, to obtain the Watana once in fifty year summer flood peak of 64,500 cfs. The August to October dimensionless hydrograph {R&M, 198la) was next multi- plied by the Watana peak flood flow to obtain the in- flow hydrograph. The inflow was then routed through the reservoir to obtain· the outflow hydrograph. Maxi- mum outflow is the sum of the outlet facility discharge and the powerhouse flows. Flows and associated water levels are illustrated in Figure E.2.83. E-2-54 ~I - - ~' - - - ·- - - - ''"" - - - - If summer floods of lesser magnitude than the fifty year event occur with the reservoir full, inflow v1i 11 match outfl ov1 up to the discharge capability of the outlet facilities and powerhouse. August floods occurring in the 32 year energy simula- tion period did not cause the reservoir to exceed ele- vation 2190 feet. Hence, no spills occurred. The sim- ulation included the August 15, 1967 flood. This flood had an instantaneous peak of 80,200 cfs at Gold Creek and an equivalent return of once in 65 years; thus demonstrating the conservative nature of the above analysis. Downstream of Watana, flood flows at Go 1 d Creek, wi 11 be reduced corresponding to the reduction in flood flow at Watana. Flood peaks at Sunshine and Susitna Station will also be attenuated, but to a lesser extent. The annual and summer flood frequency curves for Watana are illustrated in Figure E.2.84. -Flow Variability Under normal hydrologic conditions, flow from the Watana development will be totally regulated. The downstream flow will be controlled by one of the following criteria: downstream flow requirements, minimum power demand, or reservoir level operating rule curve. There will gener- ally not be significant changes ·j n mean daily flow from one day to the next. However, there can be significant variations in discharge from one season to the next and for the same month from one year to the next. Monthly and annual flow duration curves based on the monthly average flows for pre-project and post-project operating conditions for the simulation period are illustrated in Figures E.2.85 through E.2.88 for Watana, Gold Creek, Sunshine; and Susitna Station. The f1ow duration curves show a diminished pre-and-post-project difference with distance downstream of Watana. (ii) River Morphology Impacts on river morphology dur·ing Watana operation will be similar to those occurring during reservor impoundment {Section 3.2(b){ii), although flow levels will generally be increased for power operations. The reduction in stream- flow peaks, and the trapping of bedload and suspended sedi- ments will continue to significantly reduce morphological changes in the river above the Susitna-Chulitna confluence. E-2-55 The mai nstem river will tend to become tighter and better defined. Channel width reduction by vegetation encroachment will continue. The effects of ice for-ces during breakup -on the river morphology above the Chulitna River will be effective1y eliminated. Although an ice cover could form up to Devil Canyon, the rapid rise in streamfl ows which causes the initial-ice movement at breakup will be eliminated due to-- the reservoir regu1 ati on. Ir.~stead of moving downriver and forming ice jams~ the ice will thermally degrade. When it does move, it will be in a weakened state and wi 11 not cause a significant amount of damage. Occurrences of the overtopping of the gravel berms at the upstream end of sloughs will be virtually eliminated. Movement of sand and gravel bars will be minimized. Debris jams and beaver dams, which previously were washed out by high flows, will remain in place, with resultant pending. Vegetation encroachment in the sloughs and side-channels will also be evident as the high flows are reduced. Impacts at the Chulitna confluence and downstream will be similar to those occurring during reservoir impoundment. (iii) Water Qualit.t -Water Temperature • Reservoir and Outlet Water Temperature After impoundment, Watana reservoir will ex hi bit the thermal characteristics of a deep glacial lake. Deep glacial lakes commonly show temperature stratification both during winter and summer (Mathews~ 1956; Gilbert, 1973; Pharo and Carmack, 1979, Gustavson, 1975), although stratification is often relatively weak. Bradley Lake, Alaska, (Figure E.2. 89) demonstrated a weak thermocline in late July, 1980, but was virtually isothermal by late September, and demonstrated a reverse thermocline during winter months (Corps of Engineers, unpublished data). The range and seasonal variation in temperature within the Watana reservoir and for a distance downstream will change after impoundment. Balke and Waddell (1975) noted in an impoundment study that the reservoir not only reduced the range in temperature but also changed the timing of the high and low temperature. This will also be the case for the Susitna River where pre-pro- ject temperatures generally range from ooc to 14°C with the lows occurring from October through April and the ------~----------------------------~~-5~6~-- ,.,.,, - - - - - - -' -' - highs in July or August. HmoJever, to minimize the preproject to post-project temperature differences downstream, Hatana wi 11 be operated to take advantage of the temperature stratification within the reservoir. During summer~ warmer reservoir water will be withdrawn from the surface through a multipart intake structure (Figure E.2.90). The intake nearest the surface generally w"ill be used. In this way warmer waters will be passed downstream. When water is re 1 eased from the epi 1 i mni on of a deep reservoir~ there is likely to be a warming effect on the stream below the dam (Turkheim~ 1975; Baxter and Glaude, 1980). However, given the hydrological and meteorological conditions at Watana~ this may not occur. To provide quantitative predictions of the reservoir temperature behavior and outlet temperatures, reservoir thermal studies were undertaken in 1981 and 1982. To date, detailed studies have been completed for only the open water period. A one dimensional computer model, DYRESM, was used to determine the thermal regime of the Watana reservoir and the outlet temperatures. Temperature profiles were simulated for the June . through October time period using 1981 field data. Monthly reservoir temperature profiles and the mean daily inflow and outlet water temperatures are illustrated in Figures E.2.91 and E.2.92. The maximum . reservoir temperature simu1 ated was 10. 4°C and occurred in early August. This is less than the maximum recorded inflow temperature of 13°C. Although there is an initial lag in outflow temperatures in early June, it is possible to reasonably match inflow temperatures from 1 ate June to mid-September. Thus, the summer outlet temperatures from Watana will have no impact on the downstream fishery resource. In late September the natural water temperature falls to near zero degrees. Because of the large quantity of heat stored in the reservoir, it is not possible to match these natura 1 temperatures. The 1 owest out 1 et temperature that could be obtained is 4°C with the use of a lower level outlet. From September through November, reservoir water tem- peratures will gradually decrease until an ice cover is developed in late November or December. During the ice cover formation process and throughout the winter, out- E-2-57 flow temperatures will be between 0°C and 4°C but, most 1 ikely the 1 ow temperature wi 11 be 1 oc or greater. This range of outflow temperature (1°C to 4°C) can be obtai ned by selectively withdrawing water of the de- sired temperature from the appropriate port within the intake structure. Thus, when the optimum temperature, between approximately 1 °C and 4°C, has been determined, the reservoir will be operated to match that temperature as closely as possible. • Downstream Mainstem Water Temperatures In winter, the outflow temperature will initially de- crease as reservoir heat is exchanged with the cold atmosphere. The downstream temperatures were inv~sti gated with a constant 4°C outflow. and also with a temperature of 4°C up to October 15 and decreasing linearly to 1°C by January 1. This sort of analysis brackets the expected temperature regime during Watana operation. At the downstream end of Devil Canyon, the temperatures waul d be in· the range of 1. 5° to 0°C by about the first week in January. This would place the upstream edge of ooc water somewhere between Sherman and Porfage Creek by about the middle of January. This regime would continue through the remainder of the ~'linter until about April when the net heat exchange again becomes positive. During summer, outlet water temperatures will approxi- mate existing baseline water temperatures. Downstream water temperatures will essentially be unchanged from existing water temperature. For example, at Gold Creek maximum June water temperatures will approximate 13°C. Through July, temperatures will vary from 10°C to 12°C and through mid-August temperatures will remain at about 10°C. About mid-August, temperatures will begin to decrease • • Slough Water Temperatures Pre 1 i mi nary investigations show that ground water up- welling temperatures in sloughs reflect the long term water temperature of the Susitna River. Downstream of Devil Canyon, the long term average is not expected to change significantly. · Post-project summer Susitna River water temperatures downstream of Portage Creek will be similar to existing temperatures. Fall temperatures will be slight'ly warmer but should fa 11 to ooc by January and wi 11 remain at ooc unt i 1 temperatures begin to warm. In E-2-58 - - - - - - - - - - - ·- ' ,_ - - - - spring, however, water temperatures should remain cooler longer. This wi 11 counteract the warmer fall temperatures and result in the average annual water temperature remaining close to existing conditions in the Talkeetna to Devil Canyon reach. -Ice The delayed occurrence of 0°C water in the reach be 1 ow Devil Canyon will tend to delay the formation of an ice cover significantly. Since 75-80% of the ice supply be- low Talkeetna is currently from the Susitna River, the formation of the cover will be delayed until about December and ice front progression above the confluence starting in late December or early January. Depending on the water temperatures upstream, the ice cover wi 11 pro- gress to a . point between Sherman and Portage Creek. Staging will range from about 4ft at Talkeetna to about 3 ft at Sherman. The more likely occurrence is an ice cover to Portage Creek. During breakup, the cover wi 11 tend to thermally erode from both downstream and upstream. The downstream ero- 'sion will be similar to existing conditions while the upstream will be due to the warm water supplied by the reservoir as well as the positive net atmospheric heat) exchange. Due to the lower flows, the breakup of the ice cover wi 11 be 1 ess severe than the basel·i ne case. · -Suspended Sediments As the sediment laden Sus itna River enters the ~~atana reservoir, the river velocity will decrease and the larger diameter suspended sediments will settle out to . form a delta at the upstream end of the reservoir. The delta formation will be constantly adjusting to the ·changing reservoir water level. Sediment will pass through channels in the delta to be deposited over the lip of the delta. Depending on the relative densities of the reservoir water and the river water, the river water containing the finer unsettled suspended sediments will either enter the 1 ake as overflow (surface current}, interflow, or underflow (turbidity current). Trap efficiency estimates using generalized trap effi- ciency envelope curves developed by Brune (1953) indicate 90-100 percent of the incoming sediment would be trapped in a reservoir the size of Watana Reservoir. Ho\'tever, sedimentation studies at glacial lakes indicate that the Brune curve may not be appropriate for Watana. These studies have shown that the fine glacial sediment may pass through the reservoir. Indeed, glacial lakes immediately below glaciers have been reported to have E-2-59 trap efficiencies of 70-75 percent. British Columbia~ a deep glacial lake River, retains an estimated 66 percent sediment (Pharo and Carmack, 1979). Kaml oops Lake, on the Thompson of the incoming Particle diameters of 3-4 microns have been estimated to be the approximate maximum size of the sediment particles that will pass through the Watana reservoir (Peratrovich, Nottingham & Drage, 1982). By examining the particle size distribution curve {figure E2.36),_ it is estimated that about 80 percent of the incoming sediment wi 11 be trapped. For an engineering estimate of the time it would take to fill the reservoir with sediment, a conservative assump- tion of a 100 percent trap efficiency can be made. This results in· 472,500 ac-ft. of sediment being deposited after 100 years (R&M, 1982d) and is equivalent to 5 percent of total reservoir volume and 12.6 percent of the live storage. Thus, sediment deposition will not affect the operation of Watana reservoir. In the Watana reservoir, it is expected that wind m1x1ng will be significant in retaining particles less than 12 microns in suspension in the upper 50-foot water 1 ayer (Peratrovi ch, Nottingham & Drage, 1982). Re-entra i nment ·of sediment from the shall ow depths along the reservoir boundary during high ~'li nds \<Ji 11 result in short-term high turbidity levels. This will be particularly important during the summer refilling process when water levels will rise, resubmerging sediment deposited along the shoreline during the previous winter drawdown period. Slumping will occur for a number of years until the valley walls attain stability. This process will cause 1 ocally increased suspended sediment and turbidity levels. Sediment suspended during this process are expected to be silts and clays. Because of their small size these particles may stay in suspension for a long period of time. Nonetheless, during summer, the levels of suspended sediments and turbidity should remain on the order of five times less than during pre-project riverine conditions. If slumping occurs during winter, increases in suspended sediment concentrations over natural condi- . tions will occur. Since cold ambient air temperatures during the winter will freeze the valley walls, the num- ber of slides ~'lill be reduced and impacts should be minor. Suspended sediment concentrations downstream wi11 be similar to that discussed in Section 3.2(b), (iv) except that maximum particle sizes leaving the reservoir will be 3-4 microns. E-2-60 - - - - - - - - - ·-.' ,- - ..... -Turbidity Turbidity patterns may have an impact on fisheries, both in the reservoir and downstream. Turbidity in the top 100 feet of the reservoir is of primary interest. The turbidity pattern is a function of the thermal structure, wind mixing and reentrainment along the reservoir boun- daries. Turbidity patterns observed within Ek 1 utna Lake, a lake 30 miles north of Anchorage, may provide the best available physical model of turbidity within Watana Reservoir. Although it is only one tenth the size of the Watana Reservoir, its morphometric characteristics are similar to Watana. It is 7 miles long, 200 feet deep, has a surface area of 3,420 acres, and has a total stor- age of about 414,000 ac-ft. Bulk annual residence time is 1.77 years, compared to Watana•s 1.65 years. It also has 5.2 percent of its basin covered by glaciers, com- pared to 5.9 percent of Watana•s drainage area. Conse- quently, it is believed that turbidity patterns in the two bodies of water will be somewhat similar. Data collected at Ekl utna from March through October 1982 demonstrates the expected pattern at Watana. In March, turbidity beneath the ice cover was uniformly less than 10 NTU in the lower end of the lake near the intake to the Eklutna hydroelectric plant. Shortly after the ice melted in late May, but before significant glacial melt had commenced, turbidity remained at 7-10 NTU throughout the water column. By mid-June, the turbidity had risen to 14-21 NTU, but no distinct turbidity plume was evi- dent. It is believed the lake had recently completed its spring overturn, as a warming trend was evident only in the upper 3 meters. By early July a slight increase in turbidity was noted at the 1 ake bottom near the river inlet. Distinct turbidity plumes were evident as inter- flows in the upstream end of the 1 ake from 1 ate July through mid-September. Turbidity levels had significant- ly decreased by the time the plume had traveled 5 miles down the lake, as sediment was deposited in the lake. In 1 ate September,· a turbid 1 ayer was noted on the bottom of the 1 ake as river water entered as underflow. By mid- October, the lake was in its fall overturn period, with near-uniform temperatures and turbidity at about 7°C and 30-35 NTU, respectively. · In Kamloops Lake, B.C., thermal stratification of the 1 ake tended to 11 Short-circui t,. the river plumes especi a 1- ly during periods of high flow (St. John et at., 1976). The turbid plume was confined to the surface layers, resulting in a relatively short residence time of the river water during summer. St. John et al. (1976) noted that high turbidity values extended almost the entire E-2-61 length of Kamloops Lake during the summer, suggesting that the effects of dilution and particle settling were minimal due to the thermocline at 10°-6°C effectively separating the high turbidity waters in the upper layers of the 1 ake from highly transparent hypol immi on waters. This \'/as not apparent in the Ek 1 utna Lake data. Plumes were evident up to 5 miles down the lake, but they were below the thermocline. In addition, particle· settling and dilution were evident, as turbidity continually detreased down the length of the lake. The relatively cool, cloudy climate in sout.hcentral Alaska would tend to prevent a sharp thermocline from developing, so that the processes evident in Kamloops lake would not be expected in Eklutna lake, nor will they be expected in the W~tana reservoir. -Total Dissolved Solids, Conductivity, Alkalinity, Significant Ions and Metals The leaching process, as previously identified in Section 3.2.{a)(ii), is expected to result in increased levels of the above parameters within the reservoir immediately after impoundment. The magnitude of these changes cannot be quantified, but should not be significant (Peterson, 1982). Furthermore, Baxter and Glaude (1980) have found such effects are temporary and diminish with time. The effects will diminish for two reasons: First, the most soluable elements will dissolve into the water rather quickly and the rate of 1 eachate production wi 11 decrease with time. Second, much of the inorganic sedi- ment carried by the Susitna River will settle in the Watana Reservoir. The formation of an inorganic sediment blanket on· the reservoir bed will retard leaching (Peterson and Nichols, 1982}. The effects of the 1 eachi ng process should not be re- flected in the river below the dam since the leachate is expected to be confined to a small layer of water immedi- ately adjacent to the reservoir floor and the ·intake structures wi 11 be near the surface. Due to the large surface area of the proposed impound- ment, evaporation will be substantially increased over existing conditions. The annual average evaporation rate for tvtay through September at Watana is estimated at 10.0 inches or 0.3 percent of the reservoir volume (Peterson and Nichols, 1982}. During evaporation, slightly higher concentrations of dissolved substances have been found at the surface of impoundments (Love, 1961; Symons, 1969). Neglecting precipitation which would negate the effects E-2-62 -· - - - - - - - - '~ - - - of evaporation, the potential increase of less than one percent is not considered significant (Peterson and Nichols, 1982). Dissolved solid concentrations are expected to increase near the surface of the impoundment during winter. Mortimer {1941,1942) noted that the formation of ice at the reservoir surface forces dissolved solids out of the freezing water, thereby increasing concentrations of these solids at the top of the reservoir. No significant impacts should result either in the reservoir or down- stream of the dam. Precipitation of metals such as iron, manganese and other trace elements have been noticed in reservoirs resulting in reduced ~oncentrations of these elements {Neal, 1967). Oligotrophic reservoirs with high pH and high dissolved salt concentrations generally precipitate more metal than reservoirs with low pH and low dissolved salt concentra- tions. This is attributed to the dissolved salts react- ing with the metal ions and subsequently settling out {Peterson and Nichols, 1982). Average Sus itna River conductivity values for Vee Canyon and Gold Creek during winter are 70 and 125 umhos/cm at 25°C, respectively. For summer they are somewhat lower, 45 umhos/cm at 25°C for both stations. Values for pH range between 7.3 and 7.6 for the two stations. Although neither of the para- meters were high, some precipitation of metals is ex- pected to reduce the quantities suspended in the reservoir. -Dissolved Oxygen Susitna River inflow will continue to have both high dis- solved oxygen concentrations and high percentage satura- tions. The oxygen demand entering the reservoir should cant i nue to remain 1 ow. No man-made sources of oxygen demanding effluent exist upstream of the impoundment. Chemical oxygen demand (COD) measurements at Vee Canyon during 1980 and 1981 were quite low, averaging 16 mg/1. No biochemical oxygen demand values were recorded. Wastewater from the permanent town will not contribute an oxygen demand of any significance to the reservoir. All wastewater will be treated to avoid effluent re 1 a ted problems. The trees within the inundated area will have been cleared, removing the potential BOD they would have created. The 1 ayer of organic matter at the reservoir bottom will still remain and could create some short term localized oxygen depletion. However, the process of decomposition should be very slow due to the cold temperatures. E-2-63 The \tleak stratificatio.n of the reservoir may cause the oxygen levels in the hypolimnion to diminish due to lack of oxygen replenishment. The spring turnover, with its large inflow of water, will cause mixing; however, the depth to which this mixing will occur is unknown. As a resu1t, the hypolimnion could experience reduced oxygen levels. The upper 200 feet of the impoundment should maintain high D.O. due to river inflow and continual mixing. Downstream of the dam, no dissolved oxygen· changes are anticipated since water will be drawn from the upper 1 ayer of the reservoir. -Nitrogen Sueersaturation As previously noted, nitrogen supersaturation can occur below high-head dams due to spillage. During project operation, specially designed fixed cone valves will be used to discharge spills up to the once in fifty year flood. -Trophic Effects (Nutrients} Reservoir trophic status is determined in part by the relative amounts of carbon, silicon, nitrogen and phos- phorus present in a system, as well as the qua 1 ity and quantity of light penetration. The C:Si :N:P ratio indicates which nutrient levels will limit algae produc- tivity. The nutrient which is least abundant will be limiting. On this basis, it was concluded that phos- phorus will be the limiting nutrient in the Susitna impoundments. Vollenweider• s (1976) model was considered to be the most reliable in determining phosphorus concen- trations at the Watana impoundment. However, because the validity of this model is based on phosphorus data from temperate, clear water 1 akes, predicting trophic status of silt-laden water bodies with reduced light conditions and high inorganic phosphorus levels may overestimate the actual trophic status. The ~pring phosphorus concentration in phosphorus limited lakes is considered the best estimate of a lake•s trophic status. Bio-avai 1 ab 1 e phosphorus is the fraction of the total phosphorus pool which controls algae growth in a particular 1 ake. The measured dissolved orthophosphate concentration at Vee Canyon was considered to be the bio- availab1e fraction in the Susitna River. Accordingly, the average di sso 1 ved orthophosphate concentration in June was multiplied by the average annual flow to calcu- late spring phosphorus supplies. These values were in turn combined with phosphorus va 1 ues from precipitation E-2-64 - - - - - -! - - (iv) and divided by the surface area of the impoundment. The resultant spring phosphorus loading values at Watana were far below the minimum loading levels that would result in anything other than oligotrophic conditions. Likewise, upon incorporating spring loading values into Vall enwei der • s (1976) phosphorus model, the volumetric spring phosphorus concentration fell into the same range as oligotrophic lakes with similar mean depths, flushing rates, and phosphorus · loading values (Peterson and Nichols, 1982). The aforementioned trophic status predictions depend upon several assumptions that cannot be quantified on the basis of existing information. These assumptions include: • The C:Si:N:P ratio does not fluctuate to the extent that a nutrient other than phosphorus becomes 1 imit- i ng; • No appreciable amount of bio-avai1able phosphorus is released from the soil upon filling of the reservoirs; • Phosphorus loading levels are constant throughout the peak algal growth period; • June phosphorus concentrations measured at Vee Canyon correspond to the time of peak algal productivity; • Phosphorus species other than di sso 1 ved orthophosphate are not converted to a bio-available form; • Flushing rates and phosphorus sedimentation rates are constant; • Phosphorus losses occur only through sedimentation and the outlet; and • The net loss of phosphorus to sediments is proportional to the amount of phosphorus in each reservoir. Effects on Groundwater Conditions -Mai nstem As a result of the annual water level fluctuation in the reservoir, there will be localized changes in groundwater in the immediate vicinity of the reservoir. Groundwater impacts downstream wi 11 be confined to the river area. E-2-65 -Impacts on Sloughs During winter, in the Talkeetna to Devil Canyon reach, some sloughs (i.e. those nearer Talkeetna) will be adja~ cent to an ice covered section of the Susitna River and others wi11 be adjacent to an ice free section. In ice covered sections, the Susitna River will have staged to form the ice cover at project operation flows of about 10,000 cfs. The associated water level will be a few feet above norma 1 winter water 1 eve 1 s and wi 11 cause increased upwelling in the sloughs because of the in- creased gradient. The berms at · the head end of the s 1 oughs may be overtopped. A number of sloughs may be adjacent to open water sec- tions of the Susitna River. Since flows w·ill average ·approximately 10,000 cfs in winter, the associated water. level will be less than the existing baseline Susitna River water levels in winter because ice staging under present conditions yields a water level equivalent to an open water discharge that is greater than 20,000 cfs. Hence, it is expected that the winter gradient will be reduced and will result in a decreased upwelling rate in the sloughs. Duirng summer, the mainstem-slough ground water inter- action will be similar to that discussed in Section 3.2 (b}(v), with the exception that operational flows will be greater than the downstream flows during fi 11 i ng and thus upwelling rates will be closer to the natural condition than were th~ upwelling rates during filling. (v) Instream Flow Uses -Fishing Resources, Riparian Vegetation and Wildlife Habitat Impacts of project operation on the fishery resources, riparian vegetation and wildlife habitat are discussed in Chapter 3. -Navigation and Transportation Within the reservoir area, water craft navigation will extend to November because of the delay in ice cover for- mation. During winter, the· reservoir will be available for use by dogsled and snow machine. A Tthough summer flows will be reduced from natura 1 condi- tions during pruject operation, navigation and transpor- tation in the \~atana to Talkeetna reach \'Jill not be significantly impacted. Flows will be stabilized due to E-2-66 - - - ~' - - - - - a base-loaded operation. However, because of the reduced water ·levels, caution will be required in navigating various reaches. There will be less floating debris in this reach of the river, which will reduce the navigational hazards. During the fall and winter a significant reach of the river downstream of Watana will contain open water. This will allow for a longer boating season but will impede use of the river as a transportation corridor by snow machine or dog sled. Downstream of Talkeetna, ice formation may be delayed and river stage during freezeup will be increased. This may impede winter transportation across the ice. -Estuarine Salinity Salinity changes in Cook Inlet due to project operations were projected through the use of a computer model (Resource Management Associates, 1982). A comparison of the salinity impacts of average project flows with aver- age natural inflow showed that under project operation, the salinity range decreased a maximum of two parts per thousand (ppt) near the mouth of the Susitna River. The change was most notable at the end of winter when post project salinities were 1.5 ppt lower than exjsting con- ditions. At the end of September post project salinities were about 0.5 ppt higher than natural salinities because of the reduced summer freshwater inflow. Although there wi 11 be seasonal differences in salinity, the post pro- ject salinity changes should not have a significant impact. E-2-67 3.3-Devil Canyon Development (a) Watana Operation/Devil Canyon Construction Construction of the Devi 1 Canyon site· is scheduled to begin in 1995. When completed~ the Devil Canyon development wi 11 consist of a 646 foot high~ concrete arch dam~ outlet facilities capable of passing 38~500 cfs, a flipbucket spillway with a capacity of 125 ~000 cfs, an emergency spillway with a capacity of 160~000 cfs, and a 600 MW capacity powerhouse. Further information on the physical features of the Devi 1 Canyon development can be found in Section 7 of Exhibit A. The Devil Canyon diversion is designed for the 25 year recurrence interval flood. This is because of the degree of regulation· provided by Watana. Any differences in the quantity and quality of the water from existing baseline condltons during the Devil Canyon construction will be primarily due to the presence and operation of the Watana facility. Therefore~ the impacts described in Section 3.2(c) wi 11, in most cases~ be referr.ed to when discussing the impacts of Devil Canyon construct ion. ( i) Flows Operation of Watana will be unchan~ed during the construc- tion of Devil Canyon. Hence~ flows will be as discussed in Section 3.2(c). Mean monthly flows for Watana, Gold Creek~ ·Sunshine~ and Susitna Station are illustrated in Tables E.2.21, E.2.24, E.2.27~ and E.2.29. Monthly flow duration curves are shown in Figures L2.85 through E.2.88. During construction of the diversion tunnel, the flow in the mai nstem wi 11 be unaffected. Upon camp let ion of the diversion tunnels in 1996, the upstream cofferdam will be closed and flow diverted through the diversion tunnel with- out any interruption in flow. This action will dewater approximately 1,100 feet of the Susitna River between the upstream and downstream cofferdams. · Because little ice wi 11 be generated through the ~~atana Devil Canyon reach, pending during winter will be unneces- sary at Oevi 1 Canyon. Velocites through the 30 foot diameter tunnel at flows of 10,000 cfs will be 14 feet per second. · The diversion tunnel is designed to pass flood flows up to the once in 25 year summer flood, routed through Watana. The flood frequency curve for Devil Canyon is illustrated in Figure E.2.93. Initially, there is little change in discharge with frequency. This is due to the fact that the E-2-68 - - .... ' - - - - - - - - Watana Reservoir can absorb the one in fifty year flood~ discharging a maximum of 31,000 cfs {24,000 cfs through the outlet facilities and 7,000 cfs through the powerhouse [assuming minimum energy demand]). (ii) Water Quality -Water Temperatures There will be no detectable difference in water tempera- . tures at Devi I Canyon or points downstream from those discussed in Section 3.2(c)(iii) Watana Operation. -Ice Ice processes will be unchanged from those discussed in Section 3.2(c)(iii) Watana Operation except that in the event water temperatures are lowered to OoC upstream of Devi 1 Canyon, any frazi l ice produced wi 11 be passed through the diversion tunnel. -Suspended Sediment/Turbidity/Vertical Illumination Construction of the Devil Canyon facility will have im- pacts similar to those expected during the Watana con- struction. Increases in suspended sediments and turbid- ity are expected during tunnel excavation, p 1 acement of the cofferdams, blasting, excavation of gravel from bor- row areas, gravel washing, and c rearing of vegetation from the reservoir. Any impacts that occur during summer will be minimal compared to pre-Watana baseline condi- tions. However, stringent construction practices will have to be imposed during the construction of Devi 1 Canyon to prohibit suspended sediments from entering the river and negating the improved water quality, relative to suspended sediments, that wi II result when Watana becomes operational. During winter, slightly increased suspended sediment concentrations can be expected since particles less than 3-4 microns in diameter wi 11 probably pass through the reservoir. No impoundment of water wi 11 occur during the placement and existence of the cofferdam. As a result, no settling of sediments will occur. Slightly decreased vertical illumination will occur with any increase in turbidity. -Metals Similar to Watana construction, disturbances to soi Is and rock or shorelines and riverbeds wi II increase dissolved and suspended materials to the river. Although this may E-2-69 result in elevated metal levels within the construction area and downstream, the water qua 1 ity should not be . significantly impaired since substantial concentrations of many metals already exist in the river· (Section 2.3{a}). Petroleum Contamination Construction activities at Devil Canyon will increase the potential for contamination of the Susitna River by petroleum products. However, as per the \~atana construc- tion, precautions will be taken to ensure this does not happen (Section 3.2(a)i1). -Concrete Contamination The potential for concrete contamination of the Susitna River during the construction of the Devil Canyon Dam wi 11 be greater than during Watana construction because of the large volume of concrete required. It is esti- mated that 1.3 million cubic yards ofconcrete will be used in the construction of the dam. The wastewater associated with the batchi ng of the concrete caul d, if directly discharged into the river,. seriously degrade downstream water quality with subsequent fish mortality. To prevent this, the wastewater wi 11 be neutra 1 i zed and settling ponds will be employed to allow settlement of concrete cant ami nants prior to the discharge of waste- water to the river. · -Other Par~meters No additional ground water quality impacts are expected from those discussed for the proposed operation of the Watana facility • . (iii) Ground Water There wi 11 be no ground water impacts from Oevi 1 Canyon construction other than in the immediate vicinity of the construction site. ( i v) Impact on Lakes and Streams in Impoundment The perched lake adjacent to the Devn Canyon damsite wi 11 be impacted by constructi.on of the saddle dam across the low area on the south bank between the emergency spillway and the main dam. The 1 ake is just west of the downstream toe of the saddle dam and wi 11 be drained and partially filled during construcion of the saddle dam. (v) Instream Flow Uses The diversion tunnel and cofferdams will block upstream fish movement at the Devil Canyon construction site. E-2-70 JliiFI:illi'li ~· - - - (vi) - However:. the Devi 1 Canyon and Devi 1 Creek rapids, them- selves act as natural barriers to most upstream fish move- ment. Navigational impacts will be the same as during Watana operation, except that the whitewater rapids at Devil Canyon will be inaccessible because of construction activi- ties. Faci 1 it ies The construction of the De vi 1 Canyon power project wi 11 require the construction, operation and maintenance of sup- port facilities capable of providing the basic needs for a maximum population of 1,900 people (Acres 1982). The· facilities, including roads, buildings, utilities, stores, recreation facilities, etc., will be essentially completed during the first three years (1993-1995) of the proposed nine-year construction period. The Devil Canyon con- struction camp and village will be built using components from the Watana camp. The camp and village wi 11 be located approximately 2.5 miles southwest of the Devi 1 Canyon dam- site. The location and layout of the camp and village facilities are presented in Plates 70, 71, and 72 of Ex hi bit F. -Water Supply and Wastewater Treaatment The Watana water treatment and wastewater treatment p 1 ants wi 11 be reduced in size and reut i 1 i zed at De vi 1 Canyon. As a result, processes identical to those employed at Watana wi 11 be used to process the domestic water supply and treat the wastewater. The water intake has been designed to withdraw a maximum of 775,000 gallons/day to provide for the needs of the support communities, or 1 ess than 1 cfs (Acres 1982). Since the source of this supply is the Suistna River no impacts on flows \'/ill occur throughout the duration of the camps existence. The wastewater treatment facility will be sized to handle 500,000 gallons daily. The effluent from this secondary treatment facility will not affect the waste assimilative capacity of the river. The effluent wi 11 be discharged approximately 1,000 feet downstream of the intake. Prior to the completion of the wastewater treatment faci- lity, all wastewater will be chemically treated and stored for future processing by the facility. E-2-71 The applicant will obtain all the necessary permits for the water supply and waste discharge facilities. -Construction~ Operation and Maintenance Similar to Watana, the construction, operation and main-.. tenance of the camp and village could cause slight increases in turbidity and suspended sediments in the 1 ocal drainage basins · (i.e., Cheechacko Creek and Jack Long Creek). In addition, there will be a potential for accidental spillage and leakage of petroleum contaminat- ing groundwater and local streams and lakes. Through appropriate preventative techniques, these potentia 1 impacts wi 11 be minimized. (b} Watana Operat i on/Devi 1 Canyon Impoundment (i) Reservoir Filling Upon completion of the main dam to a height sufficient to allow ponding above the primary outlet facilities (eleva- tions 930 feet and 1,050 feet), the intake gates will be partially closed to raise the upstream water level from its natural level of about 850 feet. Flow wi 11 be maintained at a minimum of 5,000 cfs at Gold Creek if this process occurs between October and Apri 1. From May through September, the minimum environmental flows described in Section 3.2(b) will be released (See Table E.2.17). Once the level rises above the lower level discharge valves, the diversion gates will be permanently closed and flow passed through the fixed cone valves. Since the storage volume required before operation of the cone valves can commence is less than 76,000 acre feet, the filling process will require about one to four weeks. The reservoir will not be allowed to rise above 1135 feet for approximately one year; while the diversion tunnel is being plugged with concrete. When the dam is completed, an additional storage volume of one mi 11 iori acre feet wi 11 be required to fi 11 the reser- voir to its normal operating elevation of 1455 feet. filling will be accornpl ished as quickly as possible (cur- rently estimated to be between 5 and 8 weeks) utilizing maximum powerhouse flows at Watana. During filling of Devi1 Canyon Reservoir, Gold Creek flows ~·dll be maintained at or. above the minimum target flows depicted in Table E.2.17. { ii) . Flows Because of the two distinct filling periods, the two-stage impoundment sequence will . be sever a 1 years 1 ong, even E-2-72 - - - -''• - - I!II'Rll. - - - - (iii) ' though the actual time for filling will only be about two months long. Flows during the first stage of filling will be impacted for a short duration. Between the first stage and second stage of filling, the reservoir wi 11 not be allo~,oted to exceed 1135 feet. Thus, the Devi 1 Canyon reservoir wi 11 be more or less held at a constant level. Flows along the Susitna wi 11 be unchanged from those during De vi 1 Canyon construction (See Section 3.3{a)). During the second stage of filling, wherein 1,014,000 acre-feet are added to the De vi 1 Canyon reservoir, the Watana reservoir w-i 11 be lowered about 2.5 feet if fi 11 ing occurs during either fall or winter. Although the flow into Devll Canyon will be approximately twice normal power flow from Watana, the impact of increased flow will be minimal in the Devi 1 Canyon-Watana reach because the two sites are close to one another. Flow downstream of De vi 1 Canyon wi 11 be s 1 i ght ly reduced during this filling process. However, the time period will be short and flows wi 11 be maintained at or above the mini·- mum target flow at Gold Creek. Since actual filling times are short and since filling will likely occur in fall or winter, floods are likely to be important only during the time the reservoir is not allowed to increase above 1135 feet. If a flood should occur dur- ing this time, the cone valves are designed to pass the once in fifty year design flood of 38,500 cfs. Effects on Water Quality -Water Temperature The outlet water temperatures from Watana will be unchanged from those of the \~atana alone scenario. Because of the rapid fi 11 i ng of the De vi 1 Canyon reser- -voir, there will be minimal impact on the outlet tempera- tures at Devil Canyon during both stages of fi 11 i ng. Between the filling stages, the larger surface area of the reservoir wi 11 offer more opportunity for atmospheric heat exchange. However, s i nee the retention time wi 11 only be in the order of 4 days, it is expected that little change in water temperature wi 1l occur from that experienced under Watana along at the Devi 1 Canyon out let or downstream. E-2-73 -Ice An extensive ice cover is not expected to form on the Devil Canyon reservoir during the period wherein a pool at approximate elevation 1135 is maintained. Addition- ally, si nee winter temperatures downstream will not be significantly affected by the pool, ice processes down- stream of De vi 1 Canyon wi 11 remain the same as during Devil Canyon construction. -Suspended Sediments/Turbidity/Vertical Illumination As previously discussed, the Watana reservoir will act as a sediment trap, greatly reducing the quantity of sus- pended sediment enter·i ng the Devil Canyon reservoir. During the filling of Devi 1 Canyon from approximately elevation 1135 feet to full pool, the flow will be increased to the maximum power flow from Watana. Because of the reduced residence time, this could cause a slight increase in suspended sediment concentrations leaving Watana reservoir. However, Devil Canyon will provide additional settling capability and thus, the net result in suspended sediment concentration downstream of Devil Canyon wi 11 not be different from that during operation of Watana alone. Turbidity levels and vertical illumination will remain unchanged from Watana only operation. · · Some short-term 1ncreases in suspended sediment concen- tration and turbidity may occur within the Devil Canyon impoundment from slumping of valley walls. However, since the Oevi 1 Canyon impoundment area is characterized by a very shallow overburden 1 ayer with numerous out- croppings of bedrock, slope instability should not signi- ficantly affect turbidity and suspended sediment concen- tration. A further discussion of slope stability can be found in Appendix K of the Susitna Hydroelectric Project Geotechnical Report (Acres 1981). -Total Dissolved So 11 ds, Cpnducti vity~ A 1 kal i nity, $1gnificant Ions and Metals Similar to the process occurring dur1ng Watana filling, increases in dissolved soilds~ conductivity and most of the major ions will likely result from leaching of the impoundment soils and rocks during Devil Canyon filling. However, for initial filling~ from elevation 850 to 1135~ no significant downstream impacts are foreseen, si nee it wil1 take only about two weeks to accumulate the 76,000 acre-feet of storage. In such a short time~ insignifi- cant leaching would occur which could be detrimental to downstream water quality. E-2-74 - - - - .... ..... - - - .... ,... - - - Subsequent to initial filling and for the remainder of the filling process, fixed-cone valves will be utilized for reservoir discharge. Since they will be drawing water from well above the bottom of the impoundment and s i nee the 1 eachi ng process will be confined to a 1 ayer of water near the bottom (Peterson and Nichols, 1982) down- stream water quality should not be adversely impacted. Evaporation at the Devil Canyon reservoir surf ace wi 11 be increased above existing riverine evaporation, but this will be negated by precipitation falling directly on the reservoir. Hencet there will be no impact on total dis- solved solid concentration from evaporation. -Dissolved Oxy9en As previously discussed in Section 3.2{c), (iii) Watana Operation, water entering De vi 1 Canyon wi 11 have a high dissolved oxygen concentration and low BOD. Because of the extremely short residence times, no hypo- limentic oxygen depletion is expected to develop during either the one year that the reservoir is he 1 d near elevation 1135 feet or the final six weeks of reservoir filling. Treated wastewater will continue to be discharged down- stream of the dam, but the river flow will be more than ample to assimilate any wastes. -Nitrogen Supersaturation.· Nitrogen supersaturation will not be a concern during the filling of Devil Canyon reservoir. During the initial filling to an elevation of no greater than 1135, low level outlets \'till ,be employed. No superstauration with- in the lower level of the reservoir will occur during this two week time frame. Further, there will be no plunging discharge to entrain nitrogen. During the remainder of the filling sequence, discharge will be via the fixed cone valves. Therefore, no nitro- gen superstauration conditions are expected downstream of the dam. -Support Facilities No impacts are anticipated during the filling process as the result of the \'tithdrawal of water and the subsequent discharge of the treated wastewater from either the camp or village. E-2-75 Some localized increases in suspended sediments and tur ... bidity are expected to occur during the dismantling of the camp which may begin at this time. Using the appro- priate preventive procedures~ any impacts should be mini- mized. (iv) Groundwater No major groundwater impacts are anticipated during the impoundment of Devi 1 Canyon. The increased water level within the reservoir will be confined between bedrock walls. Downstream there may be a s 1 i ght decrease in water 1 eve 1 from reduced flows if fi 11 i ng occurs other than in August or the first 3 weeks of September. The associated change in groundwater level will be confined to the immediate area of the riverbank. ( v) Impacts on Lakes and Streams in Impoundment As the Devi 1 Canyon pool level rises, . the mouths of the tributaries entering the reservoir wi 11 be inundated for up to 1.6 miles (See Table E.2.11). Sediment transporated by these streams will be deposited at the ne~>~ stream mouth · established when the reservoir is filled. (vi) Instream Flow U~es Fisheries As Devil Canyon reservoir is filled, additional fishery habitat will become available within the reservoir. How- ever, impacts to fish habitat wi 11 occur as tributary mouths become inundated. Further information on reser- voir and downstream impacts in Chapter 3. Navigation and Transportation During filling, the rapids upstream of Devil Canyon will be inundated and white water kayaki ng opportunities will be lost. Since the reservoir will be rising about as much as 8 feet per day during filling, the reservoir will be unsafe for boating. Downstream water levels may be s 1 i ght ly lowered, but this is not expected to affect navigation because of the slight change most likely con- fined to the winter season. -Waste Assimilative Capacity Although flows in the river will be reduced during the two segments of reservoir filling, the waste assim1lative capacity of the river will not be affected. E-2-76 - - - - ·""""· ,...... - - .... (c) Watana/Devll Canyon Operation (i) Flows -Project Operation When De vi 1· Canyon comes· on 1 i ne, Watana wi 11 be operated as a peaking plant and Devil Canyon will be baseloaded. Advantage will be taken of the reservoir storage at Devil Canyon to optimize energy production whi1e at the same time providing the downstream flow requirements. Each September, the Watana reservoir will be filled to as near the maximum water level of 2190 feet as possible, while still meeting the downstream flow requirements. From October to May the reservoir will be drawn down to approximately elevation 2080 feet, although'! the reservoir will be allowed to fall to a minimum reservoir level of 2065 feet during dry years. In May, the spring runoff will b~gin to fill the reservoir. However, the reservoir will not be allowed to fill above e 1 evat ion 2185 unt i 1 1 ate August when the threat of a summer flood wi 11 have passed. If September is a wet month, the reservoir will be allowed to fi 11 an addi- tional 5 feet to elevation 2190 because the probability of significant flooding will have passed until the next spring. From November through the end of July, Dev·i 1 Canyon will be operated at the normal maximum headpond elevation of 1455 feet to optimize power production. In August, the Devil Canyon reservoir will be allowed to fall to a mini- mum level of 1405 feet. In this way, much of the August downstream flow requirement at Gold Creek can be met from water coming out of storage at Devil Canyon. This will allow most of the water entering the Watana reservoir to be stored rather than pass through the turbines and pro- duce unsalable energy. In September, the Devil Canyon reservoir will be further lowered if it is not already at its minimum elevation of 1405 feet and if the l~atana reservoir is not full. When the downstream flow require- ments diminish in October, the De vi 1 Canyon reservoir will be filled to 1455 feet. -Minimum Downstream Target Flows The minimum dormstream target flows at Gold Creek which controlled the summer operation of Watana alone will be unchanged when De vi 1 Canyon comes on line. Tab 1 e E.2 .17 illustrates these flows (A further expl ariation is pro- vided in Section 3.2(c)(i}). E-2-77 . Monthly Energy Simulations The monthlyenergy simulation program was run using the 32 years of Watana and De vi 1 Canyon synthesized flow data. Pre-project flow data is presented in Tables E.2.32 and E.2.33. (The development of the \~atana and Oevi l Canyon flow sequences used in the simulation was discussed in Sections 2.1(a) and 3.2(c), (i).) Monthly maximum, minimum, and median Watana and Devil Canyon reservoir levels for the 32 year simulation are illustrated in Figures E.2.94 and E.2.95 . • Daily Operation With both Devil Canyon and Watana operating, Watana will operate as a peaking plant since it will dis- charge directly into the Devil Canyon reservoir where the flow can be regulated. Water levels in Devi 1 Canyon will fluctuate less than one foot on a daily basis due to the peaking operation of Watana. Devi 1 Canyon will operate as a base loaded p 1 ant for the life of the project. -Mean Monthly and Annual Flows Monthly Watana, Devil Canyon and Gold Creek flows for the 32 year monthly energy simulation are presented in Tables E.2.34, E.2.35, and E.2.36. The maximum, mean, and mini- mum flows for each month are summarized and compared to pre-project flows and Watana only post-project flows (where appropriate) ih Tables E.2.22, E.2.37, and E.2.25. From October through April, the post-project flows are many times greater than the natural, unregulated flows. Post-project flows during the months of June, July, August, and September are 36, 34, 56, and 79 percent of the average mean monthly pre-project flow at Gold Creek respectively. The reductions represent the flow volume used to fill the Watana reservoir. Variations in mean . monthly post-project flows occur but the range is suhstanti ally reduced from pre-project flows. further downstream~ percentage differences between pre- and post-project flows are reduced by tributary inflows. The pre~ and post-project monthly flow summaries for Sunshine and Susitna Station are compared in Tables E.2. 30 and E.2 .31. Monthly post-project flows are presented in Tables E.2.38 and E.2.39. Although summer flows from May through October average about 8 percent less at Susitna station~ winter flows are about 100 percent greater than existing conditions. - - - - r - ..... A comparison of post-project mean monthly flows. with Watana operating alone, and with Watana and Devil Canyon both operating shows that although there are some differ- ences, the differences are minor. -Floods • Spring Floods For the 32 years simulated, no flow releases occurred between May and July at either Watana or Devi 1 Canyon. All flow was either absorbed in the Watana reservoir or passed through the respective powerhouses. The June 7~ 1964 flood of record with an annual flood recurrence interval of better than 20 years, resulted in a Watana reservoir elevation of 2151 feet at the end of June, an elevation well below the elevation at which flow is released. The maximum mean monthly discharge at Devil Canyon dur- ing the spri rtg flood period was approximately 10,500 cfs. If peak inflow into Devil Canyon reservoir con- tributed from the drainage area downstream of Watana approached this discharge~ flow at Watana would be virtua1ly shut off to maintain a Devi 1 Canyon reservoir level of 1455 feet • Lateral inflow would supply most of the power needs. However, it is unlikely the peak contribution downstream of Watana would be as large as 10,500 cfs. For example, the Gold Creek maximum his- torical one day peak flow to mean monthly flow ratio for the month of June is 2.05. If it is assumed this is valid for the drainage area between Watana and Devil Canyon, the peak 1 day June inflow during the simu- lation period would approximate 9300 cfs. For the once in fifty year flood, the downstream flow with both Watana and Devil Canyon in operation will be similar to the flow with Watana operating alone. The Watana reservoir will be drawn down sufficiently such that the once-in-fifty-year flood volume can be stored within the reservoir if the flood occurs in June. The. flow contribution at Devil Canyon for the drainage area between Watana and Devil Canyon would approximate 11,000 cfs. Hence, power needs would be met by running Devil Canyon to near capacity and reducing outflow from Watana as much as possible to prevent flow wastage. For flood events greater than the once in fifty year event and after Watana reservoir elevation reaches 2185.5, the powerhouse and out 1 et f aci 1 i ties at both Watana and Devl.l Canyon wi 11 be operated to match inflow up to the full operating capacity of the power- house and outlet facilities. If inflow to the Watana reservoir continues to be greater than outflow, the E-2-79 reservoir will gradually rise to elevation 2193. When the reservo1r level reaches 2193, the main spi l1way. gates wi 11 be opened and operated so that outflow matches inflow. Concurrent with opening the Watana main spillway gates, the main spillway gates at Devil. Canyon wi 11 be opened such that inflow matches outflow. The main spillways at both Watana and Devil Canyon will have sufficient capacity to pass the one in 10,000 year event. Peak inflow for the one in 10,000 year flood will exceed outflow capacity at Watana resulting in a slight increase above 2193 feet. At Devil Canyon there will be no increase in water leveL The dis- charges and water levels associated with a once in 10,000 year flood for both Watana and De vi 1 Canyon are illustrated in Figures E.2.83 and E.2.96. If the probable maximum flood (PMF) were to occur, the operation at Watana would be unchanged whether \~at ana is operating alone or in series with Devil Canyon. The main spillway wi 11 be operated to match inflow unt i 1 the capacity of the spillway is exceeded. At this point, the reservoir elevation would rise until it reached elevation 2200. ·If the water level exceeds elevation 2200, the erodible dike in the emergency_ spillway would be washed out and flow would be passed through the emergency spillway. The resulting total outflow through all discharge structures would be 311,000 cfs, 15,000 cfs less than the PMF. At Devil Canyon a simi 1 ar scenario wou1 d occur. The main spillway would continue to operate, passing the main spillway discharge from Watana. Once the emer- gency spillway at Watana started operating, the Devil Canyon reservoir would surcharge to 1465 and its emer- gency spillway would begin to operate. Peak outflow would occur immediately after the fuse plug eroded away. However, the peak is slightly less than the peak inflow. The inflow and outflow hydrographs for both the Watana and Devi 1 Canyon PMF are shown in Figures E~2.83 and E.2.96, respectively. Summer Floods · Although there were no flow releases. at the Watana site during August or September in the 32 year simulation, in wet years Watana and Devi 1 Canyon may produce more energy than can be used. If thf s occurs, flow will have to be released through the outlet facilities. However, on a mean monthly basis, the total discharge at Watana will be less than the Hat ana powerhouse flo~;J capacity of 19,400 cfs. Flow wi 11 only be released when the reservoir exceeds elevation 2185.5 feet. - - - ""i i - - - - ""' I - - .... - Since Watana was designed to pass the once.in·fifty year summer flood without requiring operation of the main spillway and since the capacity of the powerhouse and outlet facilities is 31,000 cfs, Watana summer flood flows will vary from a low value equal to the powerhouse flows up to 31,000 -cfs for floods with a recurrence interval less than fifty years. For the once-in-fifty-year summer flood, the Watana discharge will be maintained at 31,000 cfs but the reservoir will surcharge to 2193 feet (refer to Section. 3.2(c)(i) for the derivation of the once-in-fifty-year summer flood hydrograph). At Devil Canyon, design consideration were also estab- lished to ensure that the Devil Canyon powerhouse and ·outlet facilities will have sufficient capacity to pass the once in fifty year summer flood of 39,000 cfs with- out operating the main spillway as the resultant nitro- gen supersaturation could be detrimented to downstream fisheries. This flood is passed through the Devil Canyon reservoir without any change in water level. It includes the 31,000 cfs inflow from the once in fifty year summer flood routed through Watana plus a lateral inflow of 8000 cfs. The lateral inflow of 8000 cfs was obtained by subtracting the once-in-:-fifty-year Watana natural flood peak from the once-in-fifty-year Devi 1 Canyon natural flood peak. · In the 32 year simulation period there were four years in which flow releases occurred during high summer flow periods. Although the maximum monthly release was only 4100 cfs, the peak flow may vary well have been higher depending on the variability of the tr'ibutary inflow downstream of Watana and on the Watana reservoir level. However, the peak Devil Canyon outflow would not have exceeded the capacity of the powerhouse and outlet facilities. -Flow Variability As discussed above, at both Watana and De vi 1 Canyon, peak monthly flows may differ from mean monthly flows if the reservoir exceeds elevation 2185.5 at Watana and flow is released. For Devi 1 Canyon, as reservoir inflow from sources other than the Watana Reservoir varies, the peak outflo.w may also dlffer from the mean monthly flow. For the 32 years of simulation, the maximum Devil Canyon discharge in August was 17,900 cfs which included 14,100 cfs from Watana and 3800 cfs from tributary inflow into the Devil Canyon reservoir .. In examining flow ratios of E-2-81 one day peaks to mean monthly flow at Gold Creek for the month of August it can be seen that these rat1os vary from 1.10 to 2.40. If these ratios can be applied to the tributary inflow, then the peak inflow could have been as high as 9100 cfs. Also, if the Hatana powerhouse flow was not constant for the month, then some flow varia- bility could also be attributed to Hatana. The net result is a Devi 1 Canyon outflow that could be a constant value for the entire month or a var1able outflow that has the same mean va 1 ue but a peak on the order of 30,000 cfs. The actual variabllity.would depend on the daily inflow hydrograph for Oevi 1 Canyon. The monthly and annual flow duration curves for pre- project and post-project conditions for the 32 year simu- lation period are illustrated in Figures E.2.97 through £.2.100 for Watana, Gold Creek, Sunshine, and Susitna Station. The flow duration curves show less variability during post-project operations and a diminished pre-and post-project difference with distance downstream of Oevi 1 Canyon. (ii) Effects on Water Quality -Water Temperatures The winter time temperatures discharged from Devil Canyon will range from about 4GC to 1°C. The temperature will slowly decrease in the downstream direction because of ·heat exchange with the colder atmosphere. In January by the time the flow reaches Sherman, a drop in temperature of about 1.3°C will be expected while a drop of about 4°C wi 11 occur to Ta 1 keetna. Depending on the outflow tem- perature, the threshhold of OoC water will vary.from Talkeetna to Sherman. Throughout the winter water tem- peratures upstream of Sherman wi 11 always · be above freezing, approaching the outflow temperature as it moves upstream. The minimum temperature expected at Gold Creek will be between 0.5°C and 3GC. E-2-82 - - - - ·~ - - - The summer time temperatures will be slightly higher than those for the Watana because of the larger surface area for heat exchange. A peak temperature of about 13oC will be reached at Gold Creek about the middle of June. Through July and the first· half of August, the temper- . atures will ab about 10 to 12°C, slowly decreasing through the latter part of August to the end of September. -Ice The initiation of ice formation at Talkeetna will be delayed by several months. The larg.e volume of warm water from upstream wi 11 de 1 ay and reduce the quantity of ice supplied from the Upper Susitna River. Depending on the reservoir outflow temperatures, the ice cover wi 11 start to form by the end of January and progress a short distance upstream through February. The location of the ice front is expected to be between Talkeetna and Sherman. Staging due to the ice cover will be about 3-4 feet. The breakup in the spring wi 11 occur downstream due to warmer climatic conditions and also from the upstream front because of the warmer water from the project. The. cover will tend to thermally decay in place. Therefore, the intensity of the breakup should be less severe with fewer ice jams than the preproject occurances. -Suspended Sediments/Turbidity/Vertical Illumination Of the suspended sediments passing through the Watana reservoir, only a small percentage is expected to settle in the Devil Canyon reservoir. This is attributable to the small sizes of the particles (less than 3-4 microns in diameter) entering the reservoir and the relatively short retention time. The suspended sediment, turbidity, and vertical illumination levels that occur within the impoundment and downstream wil be only slightly reduced from that which exists at the outflow from Watana. · Some minor slumping of the reservoir walls and resuspen- sion of shoreline sediment will probably continue to occur, especially during August and September when the reservoir may be drawn down as much as 50 feet. These processes will produce short term, localized increases in suspended sediments. However, as previously noted, the overburden layer is shallow so no significant problems will arise. Additionally~ since most of this sediment wi 11 settle out, downstream increases will be minor. E-2-83 -Total Dissolved Solids, Conductivity, Alkalinity, Significant Ions and Metals As previously identified in Section 3.3{b}(i ii} the leaching process is expected to resu1t in increased levels of the aforementioned water quality properties. These effects are not expected to di~inish as rapidly as was indicated for Watana. Although leaching of the more soluable chemicals will diminish, others will continue to be leached because large quantities of inorganic sediment will not be covering the reservoir bottom. It is, how- ever, anticipated that the leachate will be confined to a layer of water near the impoundment floor and should not degrade the remainder of the reservoir or downstream water quality. As was the case at Watana, the increased surface area will lead to an increase in the amount of evaporation. However, because of the 2.0 month retention time and the mixing actions of the winds and waves, the concentrations of dissolved substances should virtually be unchanged and no adverse affect on water quality within the reservoir or downstream should occur. Since no ice cover is anticipated, no increased concen- trations of dissolved solids will result at the ice-water· interface. -Dissolved Oxygen As was previously discussed in Section 3.2 (c)(iii}, reduction of dissolved oxygen concentrations can occur in the hypolimnion of deep reservoirs. Stratification and the slow biochemical decomposition of organic matter wi 11 promote low oxygen levels near the reservoir bottom over time. No estimates of the extent of oxygen depletion are available. Within the upper layers (epilimnion} of the reservoir, dissolved oxygen concentrations wi 11 remain high. Inflow water to the impoundment will continue to have a high dissolved oxygen content and low BOD. Si nee water for energy generation is drawn from the upper 1 ayers of the · reservoir, no adverse effects to downstream oxygen levels will occur. -Nitrogen Supersaturation No supersaturated conditions ~<1i ll occur downstream of the Devil Canyon Dam. Fixed-cone valves will be employed to minimize potential nitrogen supersaturation problems for all floods with a recurrence interval less than one in fifty years. E-2-84 - - .;.~ ..... - For flood flows greater than once in fifty year flood when spillage will unavoidably occur, nitrogen super- saturation will be minimized through the installation of spi 11 age deflectors which wi 11 prevent the creation of a plunging action that could entrain air. - F ac il it i es The construction camp and village will be decommissioned upon completion of construction and filling. Localized increases in turbidity and suspended sediments will occur in the local drainage basins due to these activities, but these effects will not be significant as erosion control measures will be employed. ( i i l) · Effects on Groundwater Conditions -~ Effects on ground water conditions will be confined to the - - Devil Canyon reservoir itself. Downstream flows and hence impacts will be similar to those occurring with Watana ·operating alone. { i v) Impact on Lakes and Streams ( v) All the effects identified in Section 3.2(c)(ii) for the streams in the Watana reservoir will be experienced by the· streams flowing into the Devil Canyon reservoir listed in Table E.2.11. No lakes in the Devil Canyon impoundment will be impacted other than the previously described small lake at the Devil Canyon damsite. The tributaries down- stream of Devil Canyon wi 11 not change from the conditions established when Watana was operating alone as discussed ear 1 i er. Instream Flow Uses The effects on the fishery, wildlife habitat, and riparian vegetation are described in Chapter 3. -Navigation and Transporation The Devil Canyon reservoir will transform the heavy whitewater upstream of the dam into flat water. This will afford recreational opportunities for less experi- enced boaters but totally eliminate the whitewater kayak- ing opportunities. E-2-85 Since the Devil Canyon facility will be operated as a base loaded plant, downstream impacts should remain simi- 1 ar to the Watana only operation. The reach of river that remains free of ice may be extended somewhat further downstream. -Estuarine Salinity Salinity var1ations in Cook Inlet were computed using a numerical model of Cook Inlet (Resource Management Asso- ciates, 1982). As expected, the salinity changes from baseline conditions were almost identical with those determined for Watana operation alone. The post-project salinity range is reduced, there being lower salinities in winter and higher salinity in summer. Figure E.3.101 illustrates the comparison of annual salinity variation off the mouth of the Susitna River using mean monthly pre-and post-project Susitna Station flows. 3.4 Access Plan Impacts The Watana access route wi 11 begin with the construct ion of a 2-mi 1 e road from the Alaska Railroad at Cantwell, to the junction of the George Parks and Denali Highways. Access will then follow the existing Denali Highway for twenty-one miles. Portions of this road segment wi 11 be upgraded to meet standards necessary for the anticipated con- struction traffic. From the Denali Highway, a 42 mile road will be constructed in a southerly direction to the Watana site. Access to the De vi 1 Canyon site wi 11 be vi a a 37 mi 1 e road from Wat ana, north of the Susitna River, and a 12 mile railroad extension from Gold Creek, on the south side of the Susitna River. For a more detailed description of the access routes refer to Exhibit A, Section 1.12 and 7.12. (a) Flows Flow rates on streams crossed by the access road wi 11 not be impacted. However, localized impacts on water levels and flow velocities could occur if crossings are poorly designed. Because they do not restrict streamflow, bridge crossings are preferred to culverts or low-water crossings. Bridge supports should be located outside active channels, if possible. Where not properly designed, culverts can restrict fish movement· due to high velocities or perching . of the culvert above the streambed. Culverts are also more susceptible to icing problems, causing restricted drainage, especially during winter snowmelt periods. E-2-86 - - - -L Low-water crossings may be used in areas of infrequent, light <traffic. They should conform to the local streambed slope and are 1 to be constructed of mater1als so that water will flow over them \..-'instead of percolating through them, which would also restrict fish passage. · (b) Water Quality Most water quality impacts associated with the proposed access routes will occur during construction. The principal anticipated water quality impacts associated with construction will be in- creased suspended sediment and turbidity levels and accidental 1 eak age and sp i ll age of pet ro 1 eum products. Given proper design and construction techniques, few water quality impacts are antici- pated from the subsequent use and maintenance of these f aci 1 i- ties. {i) Turbidity and Sedimenta~ion !!""' Some of the more apparent potentia 1 sources of turbidity and sedimentation problems include: - -Instream operation of heavy equipment; Placement and types of permanent stream crossings (culverts vs. bridgesY; -Location of borrow areas; -Lateral stream transits; -Vegetative clearing; -Side hill cuts; -Disturbances to permafrost; and -Timing and schedules for construction. These potential sources of turbidity and sedimentation are discussed more fully in Chapter 3. (ii) ·contamination by Petroleum Products Contamination of water courses from accidental spills of hazardous materials, namely fuels and oils, is a major con- cern. During construction of the trans-Alaska oil pipeline, it became apparent that oil spills of various sorts were a greater problem than anticipated. Most spills occurred as a result of equipment repair, refueling and vehicle accidents. When equipment with leaky hydraulic hoses are operated in streams petroleum products are very likely to reach the water. To avoid this, vehicles and equipment will be prop- erly maintained. Water pumping for dust control, gravel processing, dewater- ing, and other purposes can also }ead to petroleum spills if proper care is not taken. Since water pumps are usually placed on river or lake banks very near the water, poor refueling practices could result in frequent oil spills into the water. E-2-87 3.5 Transmission Corridor Impacts The transmission line.can be divided into 4 segments: central (Watana to Gold. Creek), intertle (Wilow to Healy), northern (Healy to Ester), and southern (Willow to Anchorage). The centra 1 segment 1 s composed of two sectl ons; Wat ana to Cheechako Creek and Cheechako Creek to Gold Creek. Construction of the portion from the Watana damsite to Cheechako Creek wi 11 be undertaken during winter with minimal disturbance to vegetation. Hence, impact on stream flow and water quality should be minimal. From Cheechako Creek to the intertie, the transmission corridor will follow the existing trail. This should also result in minimal impacts. The Willow-Healy intertie is being built as a separate project and will be camp leted in 1984 (Commonwealth Associates, 1982). The Susitna pro- ject will add another line of towers within the same right-of-way. The impacts, then, will be similar to those experienced during intertie construction. The existing access points and construction trails will be utili zed. The Environmental Assessment Report for the i ntert i e (Commonwealth Associates,. 1982) discusses the expected environmental impacts of transmission line construction in this segment. For construction of the north and south stubs, stream crossings wi l1 be required. The potential effects will be of the same type as those dis- cussed in Section 3.4, although generally much less severe because of the limited access needed to construct a transmission line. Erosion· related problems can be caused by stream crossings vegetative clearing" siting of transmission towers, locations and methods of access, and disturbances to the permafrost. However, given proper design and ~on struct1on practices, few erosion related problems are anticipated. Contamination of local waters from accidental spills of fuels and oils is another potential water quality impact. To minimize this potential, vehicles will be properly maintained and appropriate refueling prac- tices wil1 be required. Once the transmission line has been built, there should be very few impacts associated with routine inspection and maintenance of towers and lines. Some localized temporary sedimentation and turbidity problems could occur when maintenance vehicles are required to cross wetlands and streams to repair damaged 1 i nes or towers. Permanent roads wi 11 not be built in conjunction with transmission lines. Rather, gr-asses and shrubs will be allowed to grow along the transmission corridor but will be kept trimmed so that vehicles are able to follow the right-of-way associated with the lines. Streams may need to be forded, sometimes repeatedly, in order to effect repairs. Depending on the season, crossing location, type and frequency of vehicle traffic, this could cause erosion downstream reaches. E-2-88 - - - ,.,.., 4 -AGENCY CONCERNS AND RECOMMENDATIONS Throughout the past three years, state and federal resource agencies have been consulted. Numerous water quantity and quality concerns were raised. The issues identified have been emphasized in this report. Some of the major topics include: -Flow regimes during filling and operation; -Reservoir and downstream thermal regime; -Sedimentation process in the reservoir and downstream suspended sedi- ment l~vel~ and turbidity; -Nitrogen supersaturation downstream of the dams; -Winter ice regime; -Trophic status of the reservoirs; -Dissolved oxygen levers in the reservoir and downstream; -Downstream ground water and water table impacts; -Effects on instream flow uses; -Sediment and turbidity increases during construction; -Potential contamination from accidental petroleum spills and leak- age; and -Wastewater discharge from the temporary community. A thor·ough and camp I ete comp I i ment of agency concerns and recommenda- tions will be presented pursuant to the review of this draft license application. E-2-89 5-MITIGATION, ENHANCEMENT, AND PROTECTIVE MEASURES 5.1 -Introduetion Mitigation measures were developed to protect, maintain, or enhance the the water quality and quantity of the Susitna River. These measures were developed primarily to avoid or minimize impacts to aquatic habi- tats, but they will also have a beneficial effect on other instream flow uses. . _The first phase of the mitigation process identified water quality and quantity impacts from construction, filling and operation, and incor- porated mitigative measures ·in the preconstruction planning, design, and scheduling. Three keJ. mitigation measures were incorporated into ~~he. engi ng_er-in.g..~-des+grr:·~-.f,){l) Mini mum flow requirements were selected ' 1lurTn'9'"tne salmon spawm ng season that were greater than what would be discharged if flow was selected solely from an optimum economic point of view.. (2) A multilevel intake was added to improve temperature con- trol and minimize project effects. (3) Fixed-cone valves were incor- porated to prevent nitrogen supersaturation from occurring more fre- quently than once in fifty years. Other mitigation measures incor-. porated in the project design and construction procedures are discussed· below. The second phase of the mitigation process will be the implementation of environmentally sound construction practices during the construction planning process. This will involve the education of project personnel to the proper techniques needed to minimize impacts to aquatic habi- tats. Monitoring of construction practices \till be required to identi- fy and correct construction related problems. Upon completion of con- struction~ the third phase of mitigation consists of operational monitoring and surveillance to identify problems and employ corrective measures. 5.2 -Construction The mitigation, enhancement, and protective measures included in Chapter 3.2.4(a) are appropriate for construction of the Watana and Devil Canyon facilities; the access road construction; and the transmission line construction. - - - .~ 5.3 -Mitigation of Watana Impoundment Impacts ....... The primary concerns during fi 11 i ng of the reservoir discussed 1 n Section 3 of this chapter include: -Maintenance of minimum downstream flows; -Maintenance of an acceptable downstream thermal regime throughout the year; -Changes in downstream sediment loads, deposition and flushing; E-2-90 - - - -Downstream gas supersaturation; -Eutrophication processes and trophic status; and -Effects on ground water levels and ground water upwelling rates. C"i Minimum downstream f1 ows, will be provided to mitigate the impact the· · i filling of the reservoir caul d have on downstream fish, gnd--o~t!r>· . _t_linstream flow uses. Although access may be difficult, th.~' 12,000 cfs ) fL._~~ flow at Gold Creek. in August will provide spawning salmo'rr--.{J.ccess to V most of the sloughs between Devil Canyon and Talkeetna. :Addifionillly, the selected downstream flow of 12,000 cfs will assist in-~maintaining adequate ground water levels and upwelling rates in the slou~hs. · Eutrophication was determined not be a problem and therefore no mit i ga- t ion is required. Dm>~nstream gas supersaturation wi 11 be prevented by the design of the energy disipating valves and chambers incorporated in the emergency release out 1 et. Changes in the downstream river morphology will occur but are not expected to be s i gni fi cant enough to warrant mitigation except for the mouth of some tributaries between D€vil Canyon and Talkeetna where, --G_ ·s-elective reshaping of the mouth. may be required to insure salmon \ CJ"f'~.access. . From the first winter of filling to the commencement of project opera- tion, the water temperature at the Watana low level outlet will appr;ox- imate 4°C to 5°C. Although these temperatures will be moderated some- what downstream, downstream impacts are likely to occur. No mitigation measures have been incorporated in the design to offset these 1 ow . downstream temperatures during the second and third year of the fi 11 i ng process. If during the final design phase of the project a technically acceptable cost-effective method can be developed to _mitigate this potential temperature impact, it will be incorporated into the final designs. 5.4 -Mitigation of Watana Operation Impacts The primary concerns during Watana operation are identified in Section 5. 3. (a) Flows The minimum downstream flows at Gold Creek will_ be unchanged from those provided during impoundment from May through September. However, for October through April, the minimum flow at Gold Creek will be increased to 5000 cfs. These mininum flows are not the most attractive from a project economic point of view. However, they do provide a base flm'l of sufficient magnitude that permits the development of mitigation E-2-91 measures to substantially reduce the project 1 s impact on the downstream fishery. Hence, the minimum downstream flows will provide a balance between power generation and downstream flow requirements •. To· provide stab 1 e flows downstream and minimize the potential for downstream ice jams, Watana when it is operating alone will be operated primarily as a base loaded p1ant, even though it would be desirable to operate Watana as a peaking plant. (b) Temperature and D.O. As noted in Section 3, the impoundment of the Watana reservoir will change the downstream temperature. regime of the Susitna River. Multi 1 evel intakes have been incorporated in the power plant intake structures so that water can be drawn from various depths (usually the surface). By se1ectively withdrawing water, the desired temperature can be maintained at the powerhouse tailrace and downstream. Using a reservoir temperature model, it was possible to closelY match existing Susitna River water temperatures except for periods in spring and fall. (c) Nitrogen Supersaturation Nitrogen supersaturation is avoided by the inclusion of fixed-cone valves in the outlet facilities. Fixed-cone valves have been proven effective in preventing nitrogen supersaturation (Ecological Analysts Inc. 1982). Instead of passing water over the spillway into a plunge pool, excess water is released through the va1ves. These facilities are designed to pass a once in fifty year flood event without creating supersaturated water conditions downstream. The. Watana facilities incorporate six fixed-cone valves that are capable of passing a total design flow of 24,000 cfs. 5.5-Mitigation of Devil Canyon Impo~ndment Impacts - -i - - - - Other than the continuance of the downstream flows at Gold Creek - established during the operation of Watana no additional mitigation measures· are p1 an ned during the Devil Canyon impoundment period. 5.6-Mitigation of Devil Canyon/WatanaOperation (a) Flows The downstream flow requirement at Gold Creek will be the same as for Watana operation alone. After Devil Canyon is on 1 ine, Watana will be operated as a peaking plant since the discharge feeds directly into the Devil· Canyon reservoir. The Devil Canyon reservoir will provide the flow regulation required to stabilize the downstream flows. E-2-92 c ' ·- - - (b) Temperature (c) As with Watana, multilevel intakes will be incorporated into the Devil Canyon design. Two intake ports will be needed because of the limited drawdown at Devil Canyon. Nitrogen Supersaturation The Devil Canyon Dam is designed with seven fixed~cone valves, three with a diameter of 90 inches and four more with a diameter of 102 inches. Total design capacity of the seven valves will be 38,500 cfs. E-2-93 BIBLIOGRPAHY Acres American Incorporated. 1982b. Susitna Hydroelectric· Project - Design Development Studies (Final Draft), Volume·5, Appendix B, prepared for the Alaska Power Authority. Acres American Incorporated. 1982a. Susitna Hydroelectric Project Feasibility Report: Hydrological Studies, Volume 4. Appendix A, prepared for the Alaska Power Authority. ADEC. 1978. Inventory of Water Pollution Sources and Management Actions -Maps and Tables, Alaska Department of Environmental Conservation, Division of Water Programs, Juneau, Alaska. ADEC. 1979. Water Quality Standards, Alaska Department of Environmental Conservation, Juneau, Alaska. ADF&G, 1981. Susitna Hydroelectric Project-Final Draft Report- Aquatic Habitat and Instream Flow Project, prepared for Acres American Incorporated. ADF&G, 1982. Susitna Hydroelectric Project -Final Draft Report - Aquatic Studies Program, prepared for Acres American Incorporated. Baxter, R.M. and P. Glaude, 1980. Environmental Effects of Dams and Impoundments ih C~nada: Experience and Prospects, Canadian Bulletin of Fisheries and Aquatic Sciences, Bulletin 205, Department of Fisheries and Oceans, Ottawa, Canada. Bulke E.L. and K.M. Waddell, 1975. Chemical Quality and Temperature in Flaming Gorge Reservoir, Wyoming and Utah, and the Effect of the Reservoir on the Green River.· U.S. Geological Survey, Water SUpply paper 2039-A. Bruce, G.M., 1953. Trap Efficiency of Reservoirs, Trans. Am. Geophys. Union, U.S. Department of Agriculture, Misc. ub1. 970 Bryan, ML.L, 1974. Sublacustrine Morphology and Deposition, Klhane Lake, Yukon Territory. Pages 171-187 in v.c. Bushnell and M.B. Marcus, eds. Ice Rield Ranges Research Project Scientific Results, Vo 1. 4. Dwight, L.P., 1981. Susitna Hydroelectric Project, Review of Existing Water Rights in the Susitna River Basin, prepared for Acres American Incorporated, December. EPA, 1976. Quality Criteria for Water, U.S. Environmental Protection Agency, Washington, D.C. 1~, - - - - - - - - - EPA. 1980. Water Quality Criteria Documents: Availability, Environ- mental Protection Agency, Federal Register, 45, 79318-79379, November. Flint, R., 1982. ADEC, Personal Communication, October. Freethy, R.D. and D.R. Scully, 1980. Water Resources of the Cook Inlet Basin, Alaska, USGS, Hydrological Investigations Atlas, MA-620. Gilbert, R., 1973. Processes of Underflow and Sediment Transport in a British Columbia Mountain Lake. Proceedings of the 9th Hydrology Symposium, University of Alberta, Edmonton, Canada. · Gustavson, T.C., Bathymetry and Sediment Distribution in Preglacial Malcspina Lake, Alaska, Journal of Sedimentary Petrology, 45:450- 461. Hydro-North,. 1972. Contingency Plan Study Paxson -Summit Lakes Area Trans-Alaska Pipeline, prepared for Alaska Pipeline Alyeska Pipe- line Service Co., prepared for Alyeska Pipeline Service Company. Koenings, J.P. and G.B. Kyle, 1982. Limnology and tions at· Crescent Lake {1979-1982, Part Limnology Data Summary, · Alaska Department Soldotna, Alaska. Fisheries Investiga- I: Crescent Lake of Fish and Game, LeBeau, J. 1982. ADEC, Personal Communication, October. Love, K.S, 1961. Relationship of Impoundment to Water Quality, JAWWA, Volume 53. Matthews, W.H. 1956. Physical Limnology and Sedimentation in a Glacial Lake, Bulletin of the Geological Society of America, 67: 537-552. McNeely, R.N., V.P. Neimanism and K. Dwyer, 1979. Water Quality Sourcebook --A Guide to Water Quality Parameters, Environment Canada, Inland Waters Directorate, Water Quality Branch, Ottawa, Canada. Mortimer, C. H., 1941. The Exchange of Dissolved Substances Between Mud and ~~ater in Lakes, Parts 1 and 2, Journal of Ecology, Volume 29. Mortimer, C.H~. 1942. The Exchange of Dissolved Substances Between Mud and Water in Lakes, Parts 3 and 4, Journal of Ecology, Volume 30. Neal, J.K., 1967. Reservoir Eutrophication and Dystrophication Follow- ing Impoundment, Reservoir Fish Resources Symposium, Georgia University, Athens. · · Peratrovi ch, Nottingham and Drage, Inc., 1982. Susitna Reservoir Sedimentation and Water Clarity Study (Draft), prepared for Acres American Incorporated, October. Peterson, L.A. and G. Nichols, 1982. Water Quality Effects Resulting from Impoundment of the Sus itna River, prepared for R&M Consultants, Inc., October. Phaso, ·c.M., and E.O. Carmack, 1979. Sedimentation Processes in a Short Residence -Time Intermontane Lake, Kamloops lake, British Colubm:ia, Sedimentology, 26: 523-541. Resource Management Associates, 1982. Susitna Hydroelectric Project Sa 1 i nity Model, prepared for Acres American Incorporated, October. R&M Consultants, Inc., 1982c. Susitna Hydroelectric Project, Hydraulic and Ice Studies, prepared for Acres American Incorporated, March. R&M Consultants, Inc., 1982d. Susitna Hydroelectric Project, Ice Observations 1980-81, prepared for Acres American Incorporated, August. R&M Consultants, Inc. 1982e. Unpublished Susitna River Hydroelectric Project Data. R&M Consultants, Inc. 1982f. Susitna Hydroelectric Project Slough Hydrology Preliminary Report, prepared for Acres American !ncar-· porated, October. R&M Consultants, Inc. 1982f. Unpublished Eklutna Lake Data. R&M Consultants, Inc., 1981a. Susitna Hydroelectric Project, Regional Flood Studies, prepared for Acres American Incorporated, December. R&M Consultants, Inc. 1982d. Susitna Hydroelectric Project, Reservoir Sedimentation, prepared for Acres American Incorporated, January. R&M Consultants, Inc. 1982a. Sus itna Hydroelectric Project River Morphology, prepared for Acres American Incorporated, January. R&M Consultants, Inc. 1982b. Susitna Hydroelectric Project Water Quality Interpretation 1981, prepared for Acres American Incor- porated, February. R&M Consultants, Inc. 1981b. Susitna Hydroelectric Project Water Quality Annua 1 Report 1980, prepared for Acres American I ncorpora- ted, Apri 1. R&M Consultants, Inc. 198lc. Sus i tna Hydroelectric Project Water Quality Annual Report, 1981, prepared for Acres American Incor- porated, December. Schmidt, 0., ADF&G, 1982. Personal Communication, October. Schmidt, D., ADF&G, 1982b. Personal Communication, meeting, September. - - ~I - - Siting, Marshall, 1981. Handbook of Toxic and Hazardous· Chemicals, Noyes Publications, Park Ridge, New Jersey. St. John et al., 1976. The Limnology of Kamloops Lake, B.C. Department of Environment, Vancouver, B. c. Symons, J.M., S.R. Weibel, and G.G. Robeck, 1965. Impoundment Influences on Water Quality, JAW~4A, Vol. 57, No. 1. Symons, J.M., 1969. Water Quality Behavior in Reservoirs, U.S. Public Health Service, Bureau of Water Hygiene, Cincinnati. Trihey, W., 1982b. ADF&G Personal Communication, October. Trihey, W., 1982c. ADF&G Personal Communication, meeting, September 15. Tri hey, W., 1982a. Susitna Intergravel Temperature Report (Draft). AEIDC. Turkheim, R.A., 1975. Biophysical Impacts of Arctic Hydroelectric Developments. In J.C. Day (ed), Impacts on Hydroelectric Projects and Associated Developments on Arctic Renewable Resources and the Input, University of Western Ontario, Ontario, Canada. USGS, 1981. Water Resources Data for Alaska, U.S. Geological Survey, Water-Data Report AK-80-1, Water Year 1980. U.S. ArfllY Corps of Engineers, 1982. Bradley Lake Hydroelectric Project Design Memorandum No. 2, Appendix E, February. Vollenweider, R.A., 1976. Advances in Defining Critical Loading Levels ·for Phosphorous in Lake Eutrophication, Mem. Ist. Ital, Idrobiol., 33. BIBLIOGRPAHY Acres American Incorporated, 1982c. Susitna Hydroelectric Project 1980-81 Geotechnical Report Final Draft, Volume 1, prepared for the Alaska Power Authority. Kavanagh, N. and A. Townsend, 1977. Construction-related Oil Spills Along trans-Alaska Pipeline, Joint State/Federal Fish and Wildlife Advisory Team, Alaska, JFWAT special report No. 15. Commonwealth Associates, Incorporated, 1982. Anchorage -Fairbanks Transmission Intertie, prepared for. the Alaska Power Authority, March. Joyce, M.R., L.A., Rundquist and L.l. Moulton, 1980. Gravel Removal Guidelines Manual for Arctic and Subarctic Floodplains. U.S. Fish and Wildlife Service, Biological ·Services Program FWS/OBS -80/09. Burger, C. and l. Swenson, 1977. Environmental Surveillance of Gravel Removal on the trans-Alaska Pipe 1 i ne System with recommendations for future gravel mining, Joint State Federal Fish and Wildife Advisory Team, Alaska, Special Report Series, No. 13. Lauman, T.E, 1976. Salmonid Passage at Stream-road Crossings, Oregon Dept. of Fish and Wildlife, Oregon. U.S. Forest Service, 1979. Roadway Drainage Guide for Installing Culverts to Accommodate Fish, U.S. Dept. of Agriculture, Alaska, Alaska Region Report No. 42. Gustafson, J., 1977. An evaluation of low water crossings at fish streams a 1 ong the trans-A 1 ask a pipeline system, Joint State/ Federal Fish and \~i 1 dl ife Advisory Team, Anchorage, Alaska, JFWAT Special Report No. 16. Alyeska Pipeline Service Company, 1974. Environmental and technical stipulation compliance assessment document for the trans-Alaska pipeline system, Alyeska Pipeline .Service Co., Anchorage, Alaska, Vo 1. I. Bohme~ V.E. and E.R. Brushett, 1979. Oil spill control in Alberta, 1977 Oil Spill Conference (Prevention, Behavior, Control, Cleanup), New Orleans, LA. American Petroleum Institute, Environmental Protection Agency, U.S. Coast Guard. Lindstedt, S.J., 1979. Oil Spill response planning for biologically sensitive ~reas, 1977 Oil Spill Conference (Prevention, Behavior, Control, Cleanup), New Orleans, LA., American Petroleum Institute, Environmental Protection Agency, U.S .. Coast Guard. Lantz, R.L., 1971. Guidelines for stream protection in logging opera- tions, Research Division, Oregon State Game Commission, Oregon. - - - - ..... TABLE E. 2. 1 : GAGING STATION DATA ~.Jl USGS Gage Drainage 2 Years of River Station Number Area (mi ) Record Mile ~ Denali 15291000 950 25 291 Maclaren 15291200 280 24 260(1) ·"""" Cantwell 15291500 4140 20 225 Gold Creek 15292000 6160 32 137 -Chulitna 15292400 2570 23 98 Talkeetna 15291500 2006 18 97( 1) Skwenta 15294300 2250 20 2aC1) Susitna 15294350 19400 9 26 ""' (1 ) Confluence of tributary with Susitna River • ..--\, - TABLE E..2.2: BASELINE MONTHLY FLOWS (cfs) Denali 1 Vee Devil Gold Susitna Maclaren Chulitna Canyon2 Watana2 Canyon2 Creel< Station (Paxson) Station Talkeetna Skwenta (20) (30) (32) (32) (32) (5) (21 ) (14) (15) (20) OCT Max 2135 4626 6458 7518 8212 52636 687 9314 4438 6196 He an 1132 3033 4523 5324 5654 31250 409 4859 2505 4297 Min 528 1638 2403 2867 3124 15940 249 2898 1450 1929 NOV Max 680 2200 3525 3955 3954 21548 265 3014 1786 3094 Mean 500 1449 2050 2391 2476 13247 177 1994 1146 1780 Min 192 780 1021 1146 1215 6606 95 1236 770 678 DEC Max 575 1535 2259 2905 3264 15081 190 2143 1239 287'1 Mean 317 998 1415 1665 1788 9070 118 1457 842 1267 Min 146 543 709 810 866 4279 49 891 515 628 JAN t~ax 651 1300 '1780 2212 2452 12269 162 1673 i 001 2829 Mean 246 . 824 1166 1362 1466 8205 96 1276 675 1078 Min 85 437 636 757 824 6072 44 974 504 600 FEB Max 321 1200 1560 1836 zozs 11532 140 1400 805 1821 Mean 206 722 983 1153 1242 7409 84 1099 565 903 Min 64 426 602 709 768 4993 42 820 401 490 MARCH Max 287 '1273 1560 1779 1900 9193 121 1300 743 1 zoo Mean 188 692 898 1042 1115 6562 76 978 496 809 Mw 42 408 569 664 713 4910 36 738 379 522 APRil Max 415 1702 1965 2405 2650 9803 145 1600 7'1 0 1700 Mean 230 853 1099 1267 1351 7214 87 1154 569 1016 Min 43 465 609 697 745 5531 50 700 371 607 MAY Max 4259 13751 15973 19777 21890 94143 2084 20025 7790 13460 Mean 2056 7520 10355 12190 13277 60822 802 8371 4195 7920 Min 629 2643 2857 3428 3745 29809 208 3971 1694 1635 JUNE Max 12210 34630 42842 47816 50580 176219 4297 40330 19040 40356 Mean 7306 19655 23024 26078 28095 122510 2891 22495 11610 18583 Min 4647 9909 13233 14710 15530 67838 1751 15587 7429 10650 JULY Max 12110 22890 . 28767 32388 34400 160815 4649 35570 14440 25270 Mean 9399 17079 20810 23152 23919 130980 3165 26424 10560 17089 Min 6756 12220 15871 17291 18093. 102121 2441. 22761 7080 11670 AUGUst Max 10400 22710 31435 35270 32620 138334 3741 33670 18033 20590 Mean 8124 14474 18629 20928 21727 109360 2566 22292 9331 13374 Min 3919 6597 13412 15257 16220 62368 974 11300 3787 7471 SE.PT Max 5452 12910 17206 19799 21240 104218 2439 23260 10610 13371 Mean 3356 7897 792 12414 13327 68060 1166 12003 5546 8156 Min 1822 3376 5712 6463 6881 34085 470 6424 2070 3783 ANNUAL Max 3651 7962 9833 10947 11565 59395 1276 12114 5276 10024 Mean 2723 6295 8023 9130 9670 48148 975 8748 4029 6386 Min 2127 4159 6100 7200 7200 31228 693 6078 2233 4939 NOTES: 1 Years of Record 2 Computed _J ·-.~ .1 TABLE E.2.3: INSTANTANEOUS PEAK FLOWS OF RECORD GOLD l:REEK CANTWELL DENALi MACLAREN Date cfs Date cfs Date cfs Date cfs 8/25/59 62t 300 6/23/61 30,500 8/18/63 17,000 9/13/60 8,900 6/15/62 80,600 6/15/62 47,000 6/07/64 16,000 6/14/62 6,650 6/07/64 90,700 6/07/64 50,500 9/09/65 15t800 7/18/65 7,350 6/06/66 62,600 8/11/70 20,500 8/14/67 28,200 8/14/67 7t600 8/15/67 80t200 8/10/71 60,000 7/27/68 19,000 8/10/71 9,300 8/10/71 87,400 6/22/72 45,000 8/08/71 38,200 6/17/72 7' 100 6/17/72 82,600 - TABLE E.2.4: COMPARISON OF SUSITNA REGIONAL fLOOD PEAK ESTIMATES WITH USGS METHODS fOR GOLD CREEK USGS USGS J Single Susitna 1\rea II Cook Inlet Return Station Regional Regional Regional Station location Period Estimate Estimate Estimate Estimate (Yrs.) (cfs) (cfs) (cfs) (cfs) Susitna River at Gold Creek 1.25 37' 100 37,1 DO 48,700 2 49,500 49,000 59,200 43,800 5 67,000 64,200 73,000 53,400 10 79,000 74,500 BJ,400 55,300 50 106,000 100,000 104,000 71,600. 100 118,000 110,000 115 2000 1 Based on three parameter log normal distribution and shown to three significant figures. 2 Lamke, R.D. (1970) Flood Characteristics of Alaskan Stream, USGS, Water Resources l nves t igation, 7 8-129. 3 Freet hey, G. W., and D. R. Scully ('1980) \~ater Resources of the Cook Inlet Basin, Alaska, USGS, Hydrological Investigations Atlas HA-620. - - - ~ ~, - ~ - - -! River Mile RM 149 to 144 RM 144 to 139 RM 139 to 129.5 RM 129.5. to 119 RM 119 to 104 Rl1 104 to 95 RM 95 to 61 RM 61 to 42 RH 42 to 0 TABLE E.2.~: SUSITNA RIVER REACH DEFINITIONS Average Slope 0.00195 0.00260 0.00210 0.00173 0.00153 0.00147 0.0010~ 0.00073 0.00030 Predominent Channel Pattern Single channel confined by valley walls. Frequent bedrock control points. Split channel confined by valley wall and terraces. Split channel confined occasionally by terraces and valley walls. Main chan- nels, side channels sloughs occupy valley bottom. Split channel with occasional tendency to braid. Main channel frequently flows against west valley wall. Subchannels and sloughs occupy east floodplain. Single channel frequently incised and occasional islands. Transition from split channel to braided. Occasionally bounded by terraces. Braided through the con- fluence with Chulitna and Talkeetna Rivers. Braided with occasional confinement by terraces. Combined patterns; western floodplain braided, eastern floodplain split channel. Split channel with occasional tendency to braid. Deltaic distributary channels begin forming at about RM 20. TABLE E.2.6: DEfECTION LIMITS FOR WATER QUALITY PARAMETERS Field Parameters Dissolved Oxygen· D. 0. Percent Saturation pH, pH Units Conductivity, umhos/cm ® 25°C Temperature, °C Free Carbon Dioxide Alkalinity, as CaCO~ Settleable Solids, ml/1 laboratory Parameters Ammonia Nitrogen Organic Nitrogen Kjeldahl Nitrogen Nitrate Nitrogen Nitrate Nitrogen Total Nitrogen Ortho-Phosphate Total Phosphorus Chemical Oxygen Demand Chlol'ide Color, Platinum Cobalt Units Hardness Sulfate · Total Dissolved Solids({2)) Total Suspended So lids 3 Turbidity (NTU) Gross Alpha, picocurie/liter Total Organic Carbon Total Inorganic Carbon Organic Chemicals -Endrin, ug/1 -lindane, ug/1 . -Methoxychlor, ug/1 -Toxaphene, ug/1 -2, 4-D, ug/1 -2, 4, 5-TP Silvex, ug/1 !CAP Scan{4) -Ag, Silver -AI, Aluminum -As, Arsenic -Au, Gold -B, Boron -Ba, Ba;: ium -Bi, Bismuth -Ca, Calcium -Cd, Cadmium ~ Co, Cobalt -Cr, Chromium &M Detection L ·. •t( 1.) lffil 0.1 1 +0.01 -1 0.1 1 2 0.1 0.05 0.1 0.1 0.1 0.01 0.1 0.01 0.01 1 0.2 1 1 1 1 1 o.os J 1.0 1.0 0.0002 0.004 D. 1 o.oos o. 1 0.01 o.o') o.os o. 10 o.os . 0.0') 0.05 0.0') 0.05 0.01 0.0') 0.05 ,s Detection L. . t{S) lffil .01 .1 .01 .01 .01 .01 .01 .0'1 1 .05 1 1 1 00 .00001 .00001 .00001 .001 .00001 .00001 .001 .01 .001 .o 1 .1 .01 .001 .001 .001 Criteria levels 7-17 110 6.5 -9.0 20,15 (M), 13 (Sp) 20 o.oi 10 0.01 200 so 200 ., ,500 no measurable measurable increase 25 NTU increase 15 J.D (S) DO 0.004 0.01 0.03 0.01 J 100 10 o.os 0.07..5 (S) 0.440 0.043 1.0 O.OOJS (S) 0.0012, 0.0.004 0.1 """· - .~. - - -I - - - - TABLE E.2.6: DETECTION LIMITS fOR WATER QUALITY PARAMETERS (Cont'd) R&M Detection L. ·t ( 1) lffil laborator~ Parameters (Cant 'd) -Cu, Copper 0.05 -fe, Iron 0.05 -Hg, Mercury 0.1 -K, Potassium 0.05 -Mg, Magnesium 0.05 .,.. Mn, Manganese 0.05 -Mo, Molybdenum 0.05 -Na, Sodium 0.05 -Ni, Nickel 0.05 -Pb, lead 0.05 -Pt, Platinum o.os -Sb, Antimony 0.10 -Se, Selenium 0.10 -Si, Silicon 0.05 -Sn,· Tin 0.10 -Sr, Stroll!:ium 0.05 -Ti, Titanium 0.05 ,... w, Tungsten 1.0 -v' Vanadium 0.05 -Zn, Zinc o.os -Zr, Zirconium o.os (1) . All values are expressed 1n mg/1 unless otherwise noted. s Detection l. •t (5 ) lffil .001 .01 .0001 .1 .1 .001 .001 .1 .001 .001 .001 .001 .1 .01 . .01 Criteria levels 0.01 1.0 0.00005 o.os 0.07 0.025 0.0.3 9 0.01 0.007 (S) 0.0.3 (2 )TDS -(filterable) material that passes through a standard glass fiber filter and remains after evaporation (SM p 93). (.3)TSS -(nonfilterable) material requi:red on a standard fiber filter after filtration of awell-mixed sample. (4 )ICAP SCAN-thirty-two {32) element computerized scan in parts/million (Ag, AI, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Pt, Sb, Se, Si, Sn, Sr, Ti, V , W, Zn, Zr ) • (S)USGS detection limits are taken from "1982 Water Quality laboratory Services Catalog" USGS Open-File Report 81-1016. The limits used are the limits for the most precise test available. (S) -Suggested Criteria (M) -Migration Routes (Sp) -Spawning Areas TABLE E.2. 7: PARAMETERS EXCEEDING CRITERIA BY STATION AND SEASON Parameter D.o. '::1 Saturation pH Color Phosphorus, Total (d) Total Organic Carbon Aluminum (d) Aluminum (t) Bismuth (d) Cadmium (d) Cadmium (t) Copper (d) Copper (t) Iron (d) Iron (t) Lead (t) Manganese (d) Manganese (t) Mercury (d) Mercury (t) Nickel (t) Zinc (d) Zinc (t) Stations D -Denali V -Vee Canyon G -Gold Creek C -Chulitna T -Talkeetna S -Sunshine 55 -Susitna Station Station G T G T, 5 v, G, r, s, G, 55 v, G, 55 55 v, G G, S, 55 v, G G r, 55 ss ,.. T, 5, ss u, T, 55 T, 55 T ss G, T, 5, 55 r, 5, 55 r, ss D, v, c G, T, 5, T G, r, s, T, 55 D, V, G, G, T, S r, ss G, s s G, r, s, r, s, ss r, 55 ,.. u, s, 55 v G, s, r, s. 55 Seasons S -Summer W -Winter B-Breakup 55 55 ss 55 c ss 55 Season. Criteria s L s, W, B L 8 s L 5, W, B L s s w 8 s, w s s s 5 w s, w L B s w, 8 s A w 8 s w s L s B s A w, 8 s L s 8 s L w s w 8 s A s A s w B Criteria L -Established by law as per Alaska Water Quality Standards 5 -Criteria that have been suggested but are now law_, or levels which natural waters usually do not exceed A -Alternate level to 0.02 of the 96-hour LC50 determined through bioassay - - - ·~ - - - - """ TABLE E.2.8: 1982 TURBIDITY ANALYSIS OF THE SUSITNA, CHULITNA AND TALKEETNA RIVERS CONFLUENCE AREA -3 Suspended 1 2 Sediment 4 ~ . Discharge Date Date Turbidity Concentration Location Same led Anall:_zed (NTU) (mg/1) (cfs} Susitna at Sunshine 6/3/82 6/11/82 164 71,800 -(Parks Highway Bridge) 6/10/82 6/24/82 200 403 62,100 6/17/82 6/24/82 136 .322 48,700 6/21/82 8/3/82 360 755 76,600 6/28/82 8/18/82 1,056 71,600 7/6/82 8/3/82 352 44,800 7/12/82 8/3/82 912 58,000 7/19/82 8/18/82 552 59,400 7/26/82 8/18/82 696 97,100 8/2/82 8/18/82 544 61,000 8/9/82 8/26/82 720 50,200 8/16/82 8/26/82 784 45,600 8/23/82 9/14/82 552 8/30/82 9/14/82 292 9/17/82 10/12/82 784 Susitna Below Talkeetna 5/26/82* 5/29/82 98 5/28/82* 6/2/82 256 43,600 -5/29/82* 6/2/82 140 42,900 5/30/82* 6/2/82 65 38,400 5/31/82* 6/2/82 130 39,200 6/1/82*. 6/2/82 130 47,000 r-Susitna at LRX-45 5/26/82* 5/29/82 81 Susitna near Chase5 6/3/82 6/11/82 140 (R.R. IHle 232) 6/8/82 6/24/82 130 547 """'" 6/15/82 6/24/82 94 170 20,700 6/22/82 8/3/82 74 426 6/30/82 8/18/82 376 7/8/82 8/18/82 132 18,100 ~ 7/14/82 8/3/82 728 27' 300_ 7/21/82 8/18/82 316 21,900 -7/28/82 8/18/82 300 25,600 8/4/82 8/18/82 352 18,500 8/10/82 8/26/82 364 16,700 8/18/82 8/26/82 304 8/25/82 9/14/82 244 8/31/82 9/14/82 188 9/19/82 10/12/82 328 Susitna at Vee Canyon 6/4/82 6/11/82 82 6/30/82 8/3/82 384 7/27/82 8/18/82 720 ·~~ 8/26/82 9/14/82 320 Chulitna (Canyon)6 6/4/82 6/11/82 272 6/22/82 8/3/82 680 6/29/82 8/18/82 1,424 7/7/82 8/3/82 976 7/13/82 8/18/82 1 '136 7/20/82 8/18/82 1,392 7/27/82 8/18/82 664 y-8/3/82 8/18/82 701~ 8/1.1/82 8/26/82 592 8/17/82 8/26/82 1,296 B/24/82 9/14/82 632 ,_ 9/1/82 9/14/82 316 9/18/82 . 10/12/82 1 '920 TABLE E.2.8 -(Cont'd) 3 Suspended 1 T . . 2 Sediment Date Date urb1d1ty Concentration Discharge Location Same.Ied Anal~zed (NTU) (mg/1) (cfs) Chulitna· near Confluence6 5/26/82* S/29/82 194 S/28/82* 6/2/82 272 S/29/82* 6/2/82 308 5/30/82* 6/2/82 120 S/31/82* 6/2/82 360 6/1/82* 6/2/82 324 Talkeetna at USGS Cable7 6/2/82 6/11/82 146 31'1 16,000 6/9/82 6/24/82 49 311 13,400 6/17/82 6/24/82 28 10,300 6/23/82 8/3/82 26 164 11,700 6/29/82 8/18/82 41 11,800 7/7/82 8/3/82 20 6,830 7/13/82 8/3/82 132 9,390 7/20/82 8/18/82 148 8,880 7/28/82 B/18/82 272 16,000 8/3/82. B/18/82 49 9, 730 8/10/82 B/26/82 53 7,400 8/17/82 8/26/82 82 6,490 8/24/82 9/14/82 68 8/31/82 9/14/82 37 9/20/82 10/12/82 34 Talkeetna at R.R. Bridge 7 · S/26/82* S/29/82 17 5,680 5/28/82* 6/2/82 39 6,250 S/29/82* 6/2/82 21 5,860 5/30/82* 6/2/82 20 5,660 5/31/82* 6/2/82 44 7,400 6/1/82* 6/2/82 55 9,560 Notes: 1*Refers to samples collected by R&M Consultants, all other sanples were collected by USGS. 2 R&M Consultants conducted all turbidity measurements. 3 Suspended sediment concentrations are preliminary, unpublished data provided by the U.S. Geological Survey. 4 Discharges for "Susitna at Sunshine" and "Susitna Below Talkeetna" are from the U.S. Geological Survey stream gage at the Parks Highway Bridge at Sunshine. 4 5 Discharges for "Susitna at LRX-4" and "Susitna near Chase" are from the USGS stream gage at the Alaska Railroad Bridge at Gold Creek. 6 Discharges for "Chulitna" and "Chulitna near Confluence" are from the USGS stream gage at the Parks Highway Bridge at Chulitna. 7 Discharges for "Talkeetna at USGS Cable" and "Talkeetna at R.R. Bridge" are from the USGS stream gage near Talkeetna. - - ~ - """" - - - - TABLE E.2.9: SIGNIFICANT ION CONCENTRATIONS Ranges of Concentrations (mg/1) -u stream of Pro·ect Downstream of Pro "ect Summer Winter Summer Winter --- Bicarbonate (alkalinity) 39 -81 57 -187 25 -86 45 -145 Chloride 0 -11 4 -30 1 -15 6 -35 Sulfate 2 -23 11 -39 1 -28 10 -38 Calciun (dissolved) 13 -29 23 -51 10 -37 22 -32 .~ Magnesium (dissolved) - 4 0 -16 1 - 6 1 -10 Sodium (dissolved) 2 -10 4 -23 2 - a 5 -17 Potassium (dissolved) - 7 0 - 9 1 - 4 1 - 5 - - - - Stream Name 1. unnamed 2. unnamed 3. unnamed 4. unnamed 5. unnamed 6. unname(i 7. Oshetna River B. unnamed 9. Goose Creek 10. unnamed 11. unnamed 12. unnamed 13. unnamed 14. unnamed 15. unnamed 16. unnamed 17. unnamed 18. unnamed 19. unnamed 20. unnamed 21. unnamed 22. unnamed 23. unnamed 24. unnamed Z5. unnamed Z6. unnamed Z7. unnamed 28. unnamed slough 29. unnamed slough 30. unnamed 31. Jay Creek 3Z. unnamed 33. unnamed 34. Kosina Creek 35 •. unnamed 36. unnamed 37. unnamed 38. unnamed .39. unnamed 40. unnamed 41. unnamed 4Z. unnamed 43. unnamed 44. unnamed 45. unnamed 46. unnamed 47. unnamed 48. unnamed 49. unnamed so. Wafana Creek TABLE E.Z.10: STREAMS TO BE PARTIALLY DR COMPLETELY INUNDATED BY WATANA RESERVOIR (El. 2, 185) Approximate Length Existing Approximate of Stream Susitna Elevation Stream Gradient to be River Mile at Mouth at t>fouth Inundated at Mouth (ft. msl) (ft/mile) (miles) 240.8 2,185 380 mouth only 240.0 2,175 1,000 mouth only 239.4 2,170 500 mouth only · 238.5 2,165 6DO mouth only 236.0 2,140 500 0.1 233.8 2,055 400 0.3 233.5 2,050 65 2.0 232.7 2,040 1,500 0.2 231.2 2,0.30 125 1.2 230.8 2,025 1,400 0.2 229.8 2,015 550 0.3 229.7 2,015 1,500 0.2 229.1 2,010 2,000 0.1 228.5 2,000 1,300 0.1 228.4 2,000 2,000 0.2 227.4 1 '980 1,700 0.1 226.8 1,970 250 0.6 225.0 1,930 400 0.4 224.4 1,920 1,250 0.2 221.5 1,875 230 1.0 220.9 1,865 1,000 0.2 219.Z 1,845 350 1.0 217.6 1 '830 700 0.5 Z15.1 1,785 900 0.3 ZJJ.Z 1,760 1,000 0.4 213.0 1,755 600 0.6 21Z.1 1 '750 1,200 0.3 212.0 1,750 13 0.5 (full length) Z11.7 1,745 1 ,ooo 0.3 Z10.2 1, 720 400 0.7 208.6 1,700 120 3.2 Z07. 3 1,690 300 0.9 (full 207.0 1,685 160 length) 1.0 206.9 1,685 120 4.Z 205.0 1,665 1,100 o.s (full ZD4.9 1' 665 750 length) 0.4 (full Z0.3.9 1 ,6S5 800 length) 0.7 Z03.4 1,650 350 0.5 (full Z01.8 1,635 400 length) 0.8 ZDD.7 1 ,6Z5 1,000 1.0 198.7 1,610 400 0.7 198.6 1' 605 700 0.6 197.9 1,600 500 0.6 197.1 1,595 650 0.7 196.7 1,590 1,000 0.7 196.2 1 '585 550 1.0 195.8 1,580 350 1.1 195. z 1,575 zoo 1.3 (full 194.9 1,570 zoo length) 1. 7 194.1 1,560 so 10.0 (longest fork) - - - - - ~ I TABLE E.2.10-(Cont'd) - Approximate length Existing Approximate of Stream Susitna Elevation Stream Gradient to be River Mile at Mouth at Mouth Inundated Stream Name at Mouth (ft. msl) (ft/mile) .. (miles) 50A. Delusion Creek --1,700 200 1.9 (tributary to Watana Creek) 51. unnamed 192.7 1,550 400 1.5 (full length) 52. unnamed 192.0 1,545 200 }.9 (longest fork} 5}. unnamed 190.0 1,530 1,300 0.5 54. unnamed 187 .a 1,505 1,250 0.7 -55. unnamed 186.9 1,505 2,000 1.7 56. Deadman Creek 186.7 1,500 450 2.} - - 1. 2. 3. 4. 5. 6. 7. 8. 9. 1 o. 11. 12. 12A. 12B. 12C. 13. 14. 15. 16. 17. 17A. 176. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. TABLE E.2.1'l: STREAMS TO BE PARTiALLY OR COMPLETELY INUNDATED BY DEVIL CANYON RESERVOIR (EL. 1 ,455) Approximate length Existing Approximate of Stream Susitna Elevation Stream Gradient to be River Mile at Mouth at Mouth Inundated Stream Name at Mouth (ft. msl) (ft/mile) (miles) Tsosena Creek 181.9 1,450 250 0.2 unnarned 181.2 1~440 250 0.2 unnamed slough 180.1 1,430 10 0.6 (full length) unnamed slough 179.3 1,420 250 0.1 unnamed· slough · 179.1 1,420 500 0.2 unnamed slough 177.0 1' 385 600 0.1 fog Creek 176.7 1,380 125 1.0 unnamed 175.3 1,370 75 0.6 unnamed 175.1 1,365 1' 100 0.1 unnamed 174.9 1,360 650 0.1 unnamed 174.3 1,350 350 0.3 unnamed slough 174.0. 1,350 15 2.0 (full (tributary length) unnamed to slough) --1,350 550 0.2 unnamed (tributary to slough) --1, 350 550 0.2 unnamed (tributary to slough) --1,370 1,600 0.1 unnamed slough 173.4 1,340 20 0.5 (full unnamed 17J.O 1,335 600 0.1 length) unnamed 173.0 1' 335 1,000 0.2 unnamed 172.9 1,330 1 '.300 0.2 unnamed slough 172.1 1' 320 15 0.8 (full length) unnamed (tributary to slough) --1,320 2,000 0.1 unnamed (tributary to slough) --1,320 2,000 0.1 unnamed 171.4 1 '315 2,000 0.1 unnamed 171.0 1,310 250 0.6 unnamed slough 169.5 1' 290 15 0.7 (full length) unnamed 168.8 1,280 1,400 0.2 unnamed 166.5 1,235 350 0.6 unnamed 166.0 1,230 1,250 0.2 unnamed 164.0 1,200 2,000 0.2 unnamed 163.7 1,180 1,350 0~2 Devil Creek 161.4 1,120 180 1.4 unnamed 157.0 1 '030 . 400 1. 3 unnamed 154.5 985 J,ooo 0.4 unnamed (Cheechako Creek) 152.4 950 500 1.6 - -' - ""'' - - - TABLE E.2.12: DOWNSTREAM TRIBUTARIES POTENTIALLY IMPACTED BY PROJECT OPERATION River Bank of Reason .,.._ 1 No. Name Mile Susitna for Concern 1 Portage Creek 148.9 RB fish 2 Jack long Creek 144.8 lB fish 3 Indian River 138.5 RB fish ~-4 Gold Creek 136.7 lB fish 5 Trib. ® 132.0 132.0 lB RR 6 Fourth of July Creek 131.1 RB fish 7 Sherman Creek 130.9 LB RR, fish 8 Trib. ® 128 .• 5 128.5 LB RR r-: 9 Trib. ® 127.3 127.3 lB RR 10 Skull Creek 124.7 LB RR ..... 11 Trib. ® 12j.9 123.9 RB fish 12 Deadhorse Creek 121.0 LB fish. RR 13 Tr ib. ® 121.0 121.0 RB fish 14 little Portage Creek 117.8 LB RR ~ 15 McKenzie Creek 116.7 LB fish 16 lane Creek 113.6 lB fish r 17 Gash Creek 11"1.7 LB fish 18 Trib. ® 110.1 110.1 lB RR 19 Whiskers Creek 101.2 RB fish -1Referenced by facing downstream (LB = left bank. RB = right bank). - TABLE £.2.13: SUMMARY OF SURFACE WATER AND GROUND WATER APPROPRIATIONS IN EQUIVALENT FLOW RATES Township Grid Surface Water Equivalent Ground Water Equivalent cfs ac-ft/yr cfs ac-ft/yr Susitna .153 50.0 .0498 16.3 Fish Creek .000116 .02100 .00300 2.24 Willow Creek 18.3 5,660 .153 128 Little Willow Creek .00613 1.42 .001907 1.37 Montana Creek .0196 7.85 .366 264 Chulina .00322 .797 .000831 .601 Susitna Reservoir .00465 3.36 Chulitna .00329 2.38 Kroto-Trapper Creek .0564 10.7 Kahiltna 125 37,000 Yentna ,00155 .565 Skwentna .00551 1.90 .000775 .560 - - - - -, r- 1 - - ,.... TABLE E.2.14: SUSITNA RIVER-LIMITATIONS TO NAVIGATION River Mile location* 19 52 61 127-128 151 160-161 225 291 Description Alexander Slough Head Mouth of Willow Creek Sutitna/Landing Mouth of Kashwitna River River Cross-Over near Sherman and Cross- Section 32 Devil Canyon Devil Creek Rapids Vee Canyon Denali Highway Bridge Severity Access to slough limited at low water due to shallow channel . Access from creek limited at low water Access from launching site limited at low water Shallow in riffle at low water Severe rapids at all flow levels Severe rapids at all flow levels Hazardous but accessible rapids at most flows Shallow water and frequent sand bars at low water *Reference: River t~ile Index (R&M Consultants, 1981) TABLE £.2.15: ESTHIAT£0 LO~I AND HIGH FLOWS AT ACCESS ROAD STREAt1 CROSSINGS A Drainage 1 Aria 30-Day Minimum Flow ( cfs) Peak Flows (cfs) Basin (mi ) Recurrence Interval (yrs) Recurrence Interval (yrs) 2 10 20 2 10 25 50 --· ---- Denali Highway to Watana Came Lily Creek 3.70 0.8 0.6 0.5 25 54 78 96 Seattle Creek 11.13 2.4 1. 8 1. 5 74 147 205 248 Seattle Creek Tributary 1.49 0.3 0.2 0.2 10 24 35 44 Seattle Creek Tributary 2.70 0.8 0.5 0.4 13 29 42 51 Brushkana Creek 22.00 5.5 3.8 3.4 115 217 299 354 Brushkana Creek Site 21 •. 01 4.9 3.5 3.1 121 228 315 374 Upper Deadman Creek 12.08 3.0 2.1 1.9 64 127 177 211 Deadman Creek Tributary 21.28 4.6 3.3 2.9 13B 263 363 432 Deadman Creek Tributary 14.71 3.2 2.3 2.0 97 189 262 315 Wat ana to Devil Can~on Tsusena Creek 126.61 26 19 17 780 1309 1744 2000 Devil Creek 31.0 6.7 4.8 4.2 199 369 506 597 Devil . Canyon to Gold Creek Gold Creek 25.00 5.4 3.9 3.4 162 304 418 497 1Minimum flows estimated from the following equation (Freethey and Scully, 1980, Water Resources of the Cook Inlet Basin, U.S. Geological Survey, Atlas HA-620) M d,rt b c d = aA (LP + 1) (J + 1 0) where: M = mintmum flow (cfs) d = number of days rt = recurrence interv~l (yrs) A = drainage area (mi ) LP = area of lakes and ponds (percent) J = mean minimum January air temperature (on ~I ..... - - - - ,_ -1 l. l TABLE E2.16; AVAILABLE STREAMFLOW RECORDS FOR MAJOR STREAMS CROSSED BY TRANSMISSION CORRIDOR ransm1ss1on lAB Period of Drainagz Area 1 Crossing from USGS Gage Continuous Gage Stream Name Description USGS Number Record (mi ) (approx.) Anchorage-Willow Segment Little Susitna River Near Palmer 1~290000 1948-61.9 35 mi. d/s Willow Creek Near Will ow 1~29400~ 1978-166 7 mi. d/s Fairbanks-Heal~ Segment Nenana River /11 Near Healy 15~18000 19.50-1979 1' 910 2 mi. d/s Nenana River /12 Near Healy 15~18000 1950-1979 1 '910 20 mi. d/s Tanana River At Nenana 15515500 1962-15,600 5 mi. u/s Willow-Healy Intertie Talkeetna River Near Talkeetna 15292700 1964-2,006 5 mi. d/s Susitna River At Gold Creek 15292000 1949-6,160 5 mi. u/s Indian River 82 1~ mi. u/s E. F. Chulitna Chulitna River 15292400 1958-72,1980-2,570 40 mi. u/s River near Talkeetna M.F, Chulitna Chulitna River 15292400 19~8-72, 1980-2,570 50 mi. u/s River near Talkeetna Nenana River Near Windy 15.516000 ' 1950-56,1958-73 710 5 mi. u/s Yanent Fork N/A 1 mi. u/s Healy Creek N/A 1 mi. u/s Watana-Gold Creek Segment Tsusena Creek 149 3 mi. u/s Devil Creek N/A 3 mi. u/s Susitna River At Gold Creek 15292000 1949-6,160 15 mi. u/s 1Areas for ungaged streams are at the mouth. 2d/s = downstream, u/s = upstream. Distances for ungaged stream are from the mouth. 3Averages determined through the 1980 water year at gage sites. 1 Mean Annua1 Streamflow (cfs) 206 472 3,~06 3,506 23,460 4,050 9,647 a, 748 a, 748 9,647 - - TABLE E2.17: DOWNSTREAI-1 FLOW REQUIREMENTS AT GOLD CREEK flow (cfs) !"""\ Month Dunng FiU1ng Dperatfon Jan 1 ,ooo 5,000 - feb 1,000 5,000 Mar 1,000 5,000 ·-Apr 1,000 5,000 May 6,000 6,000 -Jun 6,000 6,000 Jul 6,4aoC1) 6,480 -Aug 12,000 12,000 Sep 9 300(2) ' 9,300 -Oct 2,000 5,000 Nov 1 ,ooo 5,000 Dec 1,000 5;000 - - (1) July 1-26 6,000 27 6,000 28 7,500 29 9,000 30 10,500 """'' 31 12,000 (Z) September 1-14 12,000 15 12,000 16 10,500 17 9,000 18 7,500 -19 6,000 20 6,000 - - - 1 1 ) TABLE E2.18: WATANA INFLOW AND OUTFLOW FOR FILLING CASES ------- "IW'o 5mG ~u~• uutflow tcfs) Uutflow tcrs) Uutflow tcrs) Inflow Inflow Inflow 1 1991 1 (cfs) 1991 1992 1993 (cfs) 1991 1992 1993 (cfs) 1992 1993 Jan 1,340 1,340 1,340 1,340 1,190 1,198 1,19a 1 ,ooo 1,071 1, 071 1,071 1,000 Feb 1,138 1,138 1, 13a 1, 13a 1, 018 1,01a 1,01a 1, 000 910 910 910 910 Mar 1,028 1,028 1 ,028 1,028 919 919 919 919 a22 822 822 822 Apr 1, 261 1, 261 1,000 1,000 1,127 1,127 1 ,ooo 1,000 1,008 1, 008 1,000 1,000 May 12,158 8,690 3,276 3,276 10,870 7,402 3,649 3,649 9,715 6,247 4,016 4,016 Jun 25,326 20,005 1,000 10,527 22,644 17,323 1,103 1, 939 20,238 14,917 1,867 1, 867 Jul 22,327 5,309 9,031 1 ,ooo 19,963 2,945 2,181 2,163 17,842 2,836 2,a36 2,a36 Aug 20,142 . 14,993 a,649 15, a 59 18,DOa 12,a59 8,105 10,198 16,095 a,934 a, 713 a, 713 Sep 12,064 6,743 6,597 12,064 10,7a7 6,967 6,967 10,787 9,641 7 ,J31 7,331 7,331 Oct 5,272 5,272 1, 000 5,272 4,713 3,261 1, 000 4, 713 4,213 1,230 1, ODD 1, ODD Nov 2,352 2,352 1 ,ODD 2,352 2,102 2,102 1,000 2,102 1,879 1,a79 1,000 1,000 Dec 1,642 1,642 1, 020 1,642 1,468 1,468 1,000 1,46.8 1,312 1,312 1,000 1,000 Note: Prior to 1991, no water is stored in Watana reservoir. TABLE E2.19: FLOWS AT GOLD CREEK DURING WATANA FILLING 1u1,; )U~o ~Ul\l Dunng ~llhng Dunng t1111ng Pre- uunng f llllng Pre-Pre- Project 1991 1992 1993 Project 1991 1992 1993 Project 1991 1992 1993 Jan 1,640 1,640 1,640 1,640 1,457 1,457 1,457 1,259 1,290 1,290 1,290 1, 219 Feb 1,393 1,393 1,393 1, 393 1,238 1,238 1 '238 1,220 1,096 1, 096 1,096 1, 096 Mar 1,258 1,258 1,258 1,258 1,118 1,118 1,118 1,118 990 990 990 990 Apr 1' 544 1,544 1' 283 1,283 1, 371 1 t 371 1,244 1,244 1' 214 1,214 1,206 1,206 May 14,882 11,414 6,000 6,000 13,221 9,753 6,000 6,000 11,699 8,231 6,000 6,000 Ju·n 31,002 25,680 6,675 16,202 27,541 22,220 6,000 6,836 24,371 19,050 6,000 6,000 Jul 27,331 10,312 4,034 6,003 24,280 7,262 6,498 6,480 21,486 6,480 6,480 6,480 Aug 24,655 19,506 3,162 20,371 21,903 16,754 2,000 14,093 19,382 12,221 12,000 12,000 Sep 14,767 9,446 9,300 14,767 13,119 9,300 9,300 3,120 11 '609 9,300 9,300 9,300 Oct 6,453 6,453 2,181 6,453 5, 732 4,280 2,019 5,732 5,073 2,159 1,860 1,860 Nov 2,879 2,879 1,527 2,879 2,557 2,557 1 '455 2,557 2,263 2,263 1,384 1 ,384 Dec 2,010 2,010 1, 388 2,010 1,785 1' 785 1,317 1,785 1,580 1,580 1,268 1,268 J .J j TABLE E2.20: MONTHLY AVERAGE PRE-PROJECT AND WATANA FILLING fLOWS AT GOLD CREEK, SUNSHINE AND SUSITNA STATIONS 1 Pre-Project During filling -Month Gold Creek Sunshine Susitna Gold Creek Sunshine Susitna Oct 5,654 13,755 30,401 2,019 1 o, 120 26,766 -Nov 2,476 5,844 12,808 1,455 4,823 11,787 Dec 1,788 4,219 8,312 1,317 3,748 7,841 Jan 1,466 3,514 7,969 1,457 3,505 7,960 feb . 1,242 2,940 7,072 1,238 2,936 7,068 Mar 1,115 2,629 6,332 1' 118 2,632 6,335 .-Apr 1 '351 3,143 6,967 1,244 3,036 6,860 May 13,277 27,710 60,750 6,000 20,433 53,473 ..... Jun 28,095 64,496 124,535 6,000 42,401 102,440 Jul 23,919 63,288 132,379 6,498 45,867 114,958 Aug 21 '727 56,510 111,998 12,000 46,783 102,271 Sep 13,327 32,656 66,753 9,300 28,629 62,726 ~~ !""" Notes: 1. Assume 50% filling case, year 1992 (lowest). !"""" - - - HIBLE 2.21 POST-f'F~O.IFCT fl.O\>J ~~T Wf':1fiiH: <cf~.) . \MTMI1·l ,~;I.OHF l CN~E C 4 " ,j 6 '7 .. ::; 10 11 14 l. ;:; l (, 17 l8 l? ;~ 0 21 24 25 29 30 31 / 0 ~~J ~-~ .. 9 t 0 l 6 -~l :-J. 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'}'-~' ,.,~.~: "/H!·-;~:;) / B :·~;:~:;I ? l~H:~6 ~? -, t •'')o . .J. '7 l \. t ,~·' l-~ t. ·' ?t)?(),() s·:H I!, (I . •... ·rll. r'' ., fJ ,, • J o"l ·; I. , .. \,.'' 1.,} 01:· 'f r.·. •, r,t 1; '' ')!,!. ~ .. ,. :.· 'l (! ·:.~ :;:: I •.::< /o~·· ~:: \ n '.' '! '·t· j_ . ' .' l '. ! ~ . i ~ , \ .l ,~. 'I l' ·< -"·'1:-:;Jr" J J 1 J J l l l -J l 1 ~·---"] l 1 MONTH POB I'···P:·HJ.JE:CT F'F~ E •• F'fW JEC T l~ATANA AI. CiNF WATANfl/ItFVIL CllNYON t1AX l1IN NEAN NAX MIN NEAN MAX ·MIN rlE1~N OCT .64tie.o ~!-103.:1 4 !") ~!. ;~.. • fi 96()~'j. 1.} :)1>64. 6 6/66.:1. :i j, 9 (l () 4 7 !':i~)A4 • l 9764.~ NOlJ :~ :·; ~~ !') ) <) .1.0~!<).9 ~~():")9 ~ 1 :l.lJ<)~).t M)()4, B H.~b I', :'1 .l.l04A.4 66B:-s. ~:s 9U.::!.6 DEC ;:;~~ ~;8 t ~) 709.3 l·H4 ,. 8 1~!.:~/4.9 7~i:':'i8.2 t () ;?{)(i .I 9 :t ~,! :~ H f, I :~ 777~'J I 9 1088j .. 2 Jf:\ N 1 Tl'i, 9 b::sb. ~~ ~. '· 6 ~) ~ ~) :1.067{) • ., ? () ') :1. .1 v:".9'J. ~~ J. ).1'/'l >,to. 7 ·.;~ =·~ l • ~:s 1 <) ;!B 7 • ~:; FEB :1. ~.il;O • 4 f.,O? • :1 983.3 '7871>19 6:?~~1. 4 868!'i 4 :i :1. ~l (l? 1 < 6 fi:??~! 1 (l <;•(r~4. 6 MAR ~. :·j f.. 0 ) .~\ ::)t:-9. :1. flY~~.:~ 9()1'2.l 64.SS, :~ H09H, :~ :1. ();H r1. 6 64:')9. H 9():')9. ;~ AF'R :t96e;.o (;,()9.'2 :l099.7 0668 H(.• ~j ,t, 7 ·~ • ~~ ?·1/H, t 1i':i9'),9 !) ~l ()(I 1 4 7793.9 M (.) y ~.~'i\1?:~ > .1. ~! 0 ~·p • ~~ :1. 0:1!)/} '7 1. ~~ ~! :lfl > 0 ~:; :-~ ~·j 8 .. 9 ~~ ~·:i J. 'l • ,~) ? ::;o ~. • 0 4 () 'l:~ • 9 ~)H::~6.6 .JU N ,~::~B41.9 :1. ~~ ~~! ::< :·~. • 4 ?~H>~?;~ • 7 :1. H:~:··;;~ I· ~·j !.H~ :~ ~) • ~i f,f,;l8. :~ 6r,:u,. v ::s :i. 98 I• f, :'j~_?3.6 .JUL ~~a/6~1 .•} .1. !"j f·1 ? ~. ,() ~~()81. () > j_ 9 ~·.i j, ~'i > ()) " !::i !'·i ~~ > '1. :··; !') <} 'l ' 6 6l;2~';. ~> ;~ 4 4 ~~ • ~) 4 7:~6. 1 ,tJIJG :·oA ~" :=:; • o :1.3•H2.1 :1. 8 f:, ;~ e • :':; :1. '7:·'S'l:t •. 0 fd~'O. f.. '1'77B I H :1.1{ (11n, :.~ 3;,~(');~ I 4 ~947.5 t;EP :t. ? :;~ () :·.'i • :··; :·:j 'j' J. :1. 1'.' > ,, J.QlS1 :;!, () 1.0~Sflj. 'I . ' 4 0 7!') ,.<; ;::u t). 'l ~.::st;7~!.Y 1 C)()9 • 2 i'(·na. 4 1t.JNNUAL 9!:;:32. fy t.l()0.4 ~~M!:?:.O 9649.7 6-1~;s·~o 8 0 1 :·; • :t. 1iH:~:,), 1J' 634:~ I 8 80 j !~i. 1 <J; TABLE 2. 23 F'R£-F'fWJECT Fl Ol4 Al fHIUJ f:RI:I~I\ < d!d HOBH'XED H'f[IROLO.GY YEAR OCT NOV J.l ~· r; JAN FEB M(!R 1 !;~~~~~j 'I) ~!:·m~s ,t> . H::S? ,I) 11)~!7,1) i'Hfl, 1) i'U~t I) 2 3848.0 1300 l (l uoo.o 960.0 B2010 7-1010 3 ~) ~)'7 .l ' I) ~!7<}4,() 1 'it) I) ,I) 1M<> , 0 11)1)1) ,I) HHO , t) 4 8202.0 :~·~ 9'/ I (l noo.o 1100.0 B2.0 I (I B20~(t 5 ~)61)4, I) ~! 1 !)I) , I) 1~)1)1), I) Ul)t) .o 11)1)1) ,I) ;1 Ht), I) 6 537(),() ~!7f,{) l (l 20·4~i.O ) 79!\ • 0 14(1() I (I :1.1 (I O.c (I 7 I}'Jr)l >I) 1. 91)1) , I) 1 :~1)1), I) 9 {-II) • I) 971) >I) '14 () ,I) 8 5806,0 :HI50. 0 2142.0 :1.70 0 .(l 1 :W(I, (I 1/.Q(l, (I 9 B~! .l ~!,I) ~~!):').<} 'I) ~i~!64 ,I) :1. 9b!'),() Dt) 7 ,I) 114(1,1) 10 4811.0 2150.0 1513.0 l~4B, (I 1 :~(17 .(1 980.0 11 6:)~)(>, ,I) ~!il:'j!) >I) not>, o 184~).0 l<}~):-!. I) l:l97.t) 12 7794.0 3000.0 2691! c (I :~·1!:i;1' 0 ~. ni4, <1 lB10.0 13 ~j<} j_ b '() V<Hl.t) ~!t I) I)' I) 191)1) • () 1 ~)I) I). I) HI)!), I) 14 . 6723.0 ?800,(1 ~!(10(1' () l6(l(I,O 150'(). 0 'ooo.o 15 6447.0 n~)l). 1) 1494,1) :1.04B,I) Y66, I) n::s.o 16. 6291.() !099 I (l U1 1 ,O 960.0 B60, (I 9(1(!.{1 17 no:·>, Q ~~O<JB I I) :t 6:H , I) :1.4 i) 1), () :l:SOO,O :1. Jt)l}; I) :lS 41.?3.0 lMOdl :t!)OO,O 150010 1400.() · 1 ;.! (I (I 1 (I 19 4 91) I) >I) n:··;:s ,t) ~! I) ~·j :) , 1) :t9{~L() 191)1) 't) 19i)t) 'I) 20 4277..0 HOn dl t330.0 H)8f, • 0 9?.' c (I H:~:L (I 21 ~H ~!-1,t) .tnri,(> (ibb,l) fJ2tl,() ~'ML I) 7i' ,), I) 22 5288.0 3407.0 2290~0 ti.l J\ ~? I () 1 o:i.s; o 'i'!W10 23 !'Hl4J, I) :so'J~s. o ~!~).1.1)) I) ~!2~~,,. () ~!t)~!H ,I) 1W~!.L I) 24 4826.0 2253,0 1465.0 120'(1,(} 12(1(), (I 1000.0 25 :o ;:!.~ • !) l~)n.o 11);{4,1) fJ'J4. () /7 7, I) 7~!·). 1) 26 3739.0 17()0,0 16():~' (I 1!H6 dl 1471.0 1400.0 27 n:w. <) 1 gy;~. () 1031,1) 9'74~() S1 ~)t) ,t) ']I) I), I) 28 3874.0 ?6~10, (I ~!4():~, (I :tH29.0 1618.0 15:00.0 29 7!)/ .1. ,{) ;~ ~) ~! :·) • () !!!')89, I) 2()~!9. () lbb{-1,1) l.SI)~i ,I) ;50 4907.0 2 ~);~!'i. (I :1.61H .() U97 ,o · 1286.0 12(l(i, (I MAX H2.l~!.t) 39~H ,Q :i~!6·4 ,I) ~! 4!)2. () ~!1)28,1) ·191)1) ,() MIN 3124.() 121 ~j' 0 866,"0 :•; 824 I() 76ft d) n:~~o MEAN ;).~~)4 •. l ~!·) J.i. ;~ 178~-1. I) 1 •l.S!). 7 1 ~~4~!. ;s U.l4.H $ l I •• .. ~ J J J (~f'R Hfo1Y JliN Jtll AtJU Sf. f' ANNUAL Hi'<),() U~HI),I) :1.9Mt),i) ~!i!61)1) ,Q t98tit),Q H:i<H , t) 8032.1 u.11.o 14(190.0 :?0790.0 ~!n;1o. (I· 1 ')67<~c <1 · n21o. o 9106.0 'Ji!l)) I) ~)4!9.1) :s~!~.S/1>. J. U>.~?t>.O 2<>nl),o 144Ht>, 0 ?f)~):;! .1 161 :L (! 19::>/(ll (i 27:~20 .1 ~! (12(1(1 1 (I 2061(h 0 1:)?70.0 ·1009(lf4 1~!~~j ,I) AnU<),t) 2~)~!~-jl), I) ~!1):~61>. Q ~!6!1)1),1) :~. ~!'nl) ,,> 9681.6 '·j~oo.o 9319 .() ~l ~\.B (!(I I (I :0~1{10, (I )!~P:W, 0 14:~90. 0 1M!fi6 • 4 9~)0 ,I) :1. 7MIO ,I) :s:~:H1> t~> .11()91) .t ~~ 1Hi:ii). Q 1 fi,Bt),!) H473.3 ~?00.0 13nHI~ (I :HH 6 (I , (I ~!:~:u (II o 20t~40. 0 19800,0 H1:n~4, 1 H5~~~, l) 1 ~!901) ,!) 2~)71)1) ,I) 2',~f!HI). 0 n~)4<>. o lS~)I), I) '1476. 4 1250.0 g)I(S'()' (I ~!:~;7,;~(1' () j! :)(1 (I (I • (l ~Hl8(l.O J6920 I() Ht!)~)9, 'i J~!)l) 1 I) .l !'•i7BO) I) l~)f'i\SI) ,I) ~!:!9Bt>, Q ~~:S~}91) '() 2t)~) 11) ,I) 9712.3 2M'i01 (I tn6(1,(1 ;.!IJ-1!)(110 ?4570.0 22100.0 1 :t~~·/ (I c (I 1(1BM, :~ :1./()1),1) 1 ~!~)91). () ·}~1~.!71) '0 ~!:'HI~)t) , 0 2:S~Hit) ,I) HW90 II) J.1. ~jb5 ~ 2 B:HI.(l :J.1J(IWdl :l6(lQ(II 0 3~400.0 ~!.:{610. 0 1n2<1, <1 11(17?.9 74f) ,() •l.'S () J , I) :>O!Hll) ,Q 2:~9~)1). () 16441),1) Y~·i71 , I) 9799.6 U6(l,(l :t:l9 1/(l,(} 25720.0 ?.784(1,(1 j!:i 1~~()' (I 1V:~!i0. 0 lO:t6B.B 17/!'j ,I) 9fl <) ~j It) ;s ~! ni t> • o :t 9861), () :~uno .o un>o. <> 94:u .a 1,1(,7 .• () :t !)1 fl()' (i ~! S'~il () .(I ~!fl8(l(~' 0 3262(11 (l 1(,870. 0 11218. ~ 1 9 J.t), I) .tblfj(),t) :u ~j ~·j() > 0 ~!/1 ~~!I) • 0 171 7th l) BfU6, t) 'I:HO, 6 :1.02?.0 985:? I (I ~lo::,~?:~. o 1.Bc1n .<• 16:~~]~~ 1 (I 9776.0 7?00.1 :1. Of}!)> t) .tl;suo.<> .lH6iSl) ,Q ~!~! 661). () 199fJI), I) nu .o 7:191.2 108?..0 37ft~) 1(1 J~9;~(1. () j!:~nH11 (I 3l910.0 14440.(1 1(12!)1 1 (I 1711),.1) ~! .l891) >I) :sH:so .o ~~v'Jo .o 19~!91). () 1 ~HI)t) ,t) 10.HB5, 5 1 M~'J ,. (l 82:~:1' (I :UB(I(l.(l 1 B~? !'I {I. 0 /.o:?9o.o 9(174.() f) (it~ 6. j! ?'n.<> 1/d i)l), I) 1 i'H7t>. () Ul81)l), 0 1 "~!~!I). Q :t ~! ~! !')l) ' I) 7.:Bl, 0 :t ~·j9;~, (I :i.!)3!)(11 (I :\2:no 1 o 27720.0 18(19(110 t6:n(l, o :1.<1n:s.1 B'J~Lt) 1 ~!b~!l). 0 ~~ 1) ;~(-II), I) H194t).O 19Ht>Q .o 6lHH ,t) 8.l99.3 :1. 6B(I ·~(I lj!6IW1 (I :r7970. 0 :?~!870. () H\:HOdi 1U,4<1~0 1(ll09.0 1 /!)~!,I) :1.! 9!')1), I) .l C]l)~)l) • 0 2:t Q~!Q. C) 1 b~S9t); 0 H6t}7 ,I) !1194.5 :t.4:HI~ 0 1:Ul:i'O. 0 24690.(1 ~!HB80, 1 2(140(1, 0 10770.0 9489.3 26~il) • Q 21H9t),t) :'it)~iHO, Q 3441)1).0 3~6~!1),0 21 ~!41) ,I) 1151!5 .2 74~). () 374th(i 1 ~i~i~~o, <1 :t B(li}J I (l 16:n(l~ (I 6881.0 noo .t 1]~)1.3 D~!7b.7 ?.tJt)9!')' 1 2:-srn9,4 21 ~~~6. 7 13:iU.~! 9670.1 ~ -.J J I I ! .~ ---- ) ~ 1 .... 1 TABLE 2.24 POST-PROJECT FLtiWH AT GOLD CREfK <cfs) . WtiTMlA t CASE C YEAR 1 2 3 4 6 7 B 9 10 11 l,2 13 14 15 16 1? 18 19 20 21 ''l"l .t .. k 23 ~.!4 25 26 28 29 30 31 ·z ") \J"" MAX MIN Ml='MJ OCT NOV £•EC ,I(.:N F E.B MAR . tif.l y . .um .1111· SEF' 7279.7 10215.7 11555.4 9917.5 9104.5 9237.7 7573.6 0406.6 0021.8 »024.0 12000.0 9281.6 6389.8 6833.4 7\~oso.s n.u.sr 6H7 •. o 65SB.s 5\'B9.l 1o:H4.:~ 7~07.6 · 7561.5 D<,oo.o · 9:~oo,c1 8061.0 107JH~O 12~16.4 10490.5 9316.5 0391.7 7623.6 652Y,J 11599.0 9076.1 12000.0 9300.0 10185,6 1l490.9 11Bl6.4 9990.5 9136.5 B331.7 8318.6 15608.4 10009,9 7405.~ .12000,0 9300,0 7Q76,J 7092.~ 11616.4 10190.5 9316.5 0291.7 7938.6 13952.5 10735.5 7967.2 ~2000.0 9300.0 7194~8 7955,0 12161,4 10AH4.S 9716.5 8611.7 7903.6 7H59,R 10153.2 10~21,7 16~76,1 9300,0 8468.7 9094.0 11416.4 9870.5 92tl6.5 8451.7. 765J.6 14206.0 15256.3 14077.5 15432.0 13410.6 9376.5 11044,0 12~5H.4 10590,5 9816,5 8711·,7 790J,6 10574,5 i200B.4 R109.3 12000.0 12213,0 11782.5 11940.0 1JJH0,4 10855,5 9623.5 0659.7 8236.6 9746.4 11565.0 7883~0 12000.0 9121.3 6874.9 6~33,2 8170,4 1033R.S 9623,5 8491.7 79~3.6 12818.1 9828,6 921!7,S 16208,B 11843.4 101~8.5 10843.9 12316.4 10735,5 9768,5 0708.7 HOOJ,6 12J17.7 7167,0 0286.8 12000.0 9300,0 8?27.4 10993.9 12810.4 l134~.5 10070.5 9321.7 9353,6 13B38.4 11969.2 9477.6 12000,0 9300.0 /328.7 1069~.0 12216.4 10770.5 9016.5 0911.7 0403.6 9290.0 24151.9 9985.7 14666.9 10429.8 10293.5 10794.0 12116.4 10490.~ 9Sl6.5 8511.7 7533.6 35342.2 10296,0 15140.5 15146.6 9300.0 7777.9 10244.0 11610.4 99~8.5 9282.5 0224.1 7449.6 6061.J 26091.6 7087.3 12000.0 9300.0 7290.9 6966,6 767H.9 .9657.5 9~76,5 8411.7 8063,6 9735.6 9469,8 9771,5 12000.0 13506,1 10775.5 10092.0 11747.4 10290.5 9616.5 9911.7 0478.6 7809,8 13486.7 R261.6 12000.0 9300.0 6615.5 690~.6 7984.7 10390.5 9716.5 B?11.7 7810.6 1206616 11635,B 10362.9 '2704.4 119~0,6 8470,5 10J46,Y 12171.4 10871.5 10216.5 9411.7 3613.6 12739.5 13601.8 10042.6 12000.0 9300.0 6581,8 6882,1 7030,0 7B3B.5 9238.~ 834417 77~5.6 7168.9 7865.7 6H51.7 12000.0 9300,0 6628,H 7003.5 11012.9 7518,2 6506.1 6770.9 5919.3 7271.7 921J.6 H9?7.1 12000,0 9300,0 7491.4 · 7700,8 8481.6 7681.2 6677,1 6047,7 6091.4 63HY,6 104H4.0 7762.3 13149,0 9300.0. 0728.1 110116.1 12626.4 11129.5 10J44.5. 9334.7 0413.6 101J4.9 16601i7 1672.0 120~0.0 9300.0 6221.8 6864.6 11581.4 10090.5 9516,~ 8511.7 7730.6 6206.9 89j4,3 6404.0 12000.0 9300.0 645J,O 6741.5 7124,6 7179.3 6725.3 H2J5.7 7695,6 127JJ,J" 7948,9 7482.9 12000.0 9300,0 6551.3 7008.3 8137.7 7574.4 6719.3 6895.6 6120.8 9024.5 13490.5 11000.7 12000.0 9300,0 9Bl6,0 9907,0 1t197,t 9864,5 9266.5 0411.7 HQ76.6 9560,3 9J50.3 6512.6 12000.0 H050.5 6na.2 7351.4 s~n.5 7~>16.~~ M46.5 7982.3 s~ie:~.6 9MJ~).~~ H'M)1,3 79Clll,t ~~·aoo.o 93oo,o 7469.2 10067.7 12705.4 10919.5 9984,5 9116.7 8405.6 8669.0 6616.9 724~.2 12000.0 9300.0. 7014.9 7274.0 8119,1 7475.8 6~37.4 6576.7 ~811.1 9810.6 690Rt0 11710.4 12000.0 9300,0 6942r2 11972.1 12532,4 10638.5 9782.5 · H911,7 8373,6 0080.2 11112.6 15151.9 12030.3 ,9300,0 10320.3 11979.9 11889i5 10344.1 9552.1 8626.0 8071,~ 10118.3 6000.0 979~.0 26494.0 10461.1 11782.5 11979.9 13380.4 11342.5 10344.5 6221 .a 6741,5 7678.9 7179.3 6437.0 !-lCJI~Lt) 91WL 7 ·11~.'.·?.~.~.( t1Jt)'l,A !19~~1 .·t 9411.7 Mi76. 7 H::{~I.'L 1 9353.6 1R1J4,9 26091.6 15131.9 26474.0 1J506a1 5811.1 6061.3 6000.0 6404.0 12000.0 8050.5 .· 77A0.1 104tl4.9 11419.~ 9J~~.A l~l7R.4 9Rl9.A · 9H5.8 7B:H.3 9~)95. 1 1 (l;l,BO, 5 96:~5. 0 9HB2.5 111\68.8 10384.1 11)162.0 9fl74.3 9978.8 :to:n6.1. 11381.9 H~!6:L :~ 104b8.3 I) :X,()~\ I 7 1 ()i)~j6. 4 1 (l~'i93. 9 1().~54.4 8:1.28.7 7947.1 8181.2 U2R9.7 BM~i. 7 ff.~70 .1 Bt.71. 0 ·~~~·17. 6 ~'2~):) I 0 9:us. 3 B~!.:S:5 ~ 0 .1M69.9 11372.4 11468.8 7831 .3 9745.4 TAnLE 2.25 ~10NTHI.Y NtiXH11JNs WOHl1tJNr tlND MFAN FI..Ot4H f.'IT BOU) CJ.::f~FI< 11DNTH f'OH r ··PRO.JECT Pf~E-F'f::OJE:CT . ldtHANfl f.1LfJNF' tdf1T fiNti/TJF. V :0; Cf1NYfJN Mr1X HIN ' NEAN > MAX MIN MEAN MAX MIN MEAN . OCT 82:L2.0 :n ~~1 .o r)f..5·'4. 3 :1 :1. i'B~~. :~·; o=?~:!:l.. e IH> :1.4, 0 :1.0983.0 o-1·r;;:~, ~?. · Tlb4.9 NOV :Hl:H .t) 1. ~~ :1. r) • t> ·~~4//>,,"S 1.:1.91'9~9 6 74 J. ~ ~) 9.lnti."/ :I.~.H4n.u 7H);~, 9 'll>:~o. n DEC 3264.0 866;{} l?BB.<> 13380.4 'N,7B, 9 :I.(J (", 9 :~ I ::s. :1. :~ l. 34 •· 1 H<J4(1 I!) u. :n<~. 9 JAN 2--1::5~~~ ~ t) w.!4 ,(> 146!:~~7 J.US4~~.r-; i' t 'i' 9 • ~~ 9?!)7, H .1.~~o4r-;. a 7 4 ~~:i • 9 1. ():)9.~ + 7 FE:f:. 202€1.0 /68.() :1.~~42.3. j 0~~44. ~:i (; -1 ::s I' ' (l WJ~H.:I. :t:ll.\52.8 (ll.j !'$ 7' :-s 1() :1. ()()I 9 MAR 1.? !)<) > I) 'J :t. :~ > <) U.:l.4 .H 94Ud7 6 ;) 'l (; • 7 m~ :.~~$."I ;1.!)61)4.~! 66:t.H,J. 9~:!8:::i. 6 A F' F~ 26~i0+0 '14~·; .o :l]~·ii,.3 9~~53.6 r·;B~.:t.1. Tl40 I :r. 9/~'i9. 4 :w :H'; I 4 ~}:1, (}(I I 4 t-hiY ~!1.H90.0 .1/4r·; .o c~::!/6. i' l!·}:l.:~4 .9 !-, 0 ,1; 3. > :;s :tl)4l)4,')' :1. ~~:~80 >I) b I) 1)() t () H'/()6.3 • .JUN :i0580. 0 :t :'.i r:; :~ o • o ;Hl o 9 !7i • 1 2b09l.6 6000.0 ,.:liH!/,!"1 :1.:~ :~ 0 :"j • 2 6{100 <· () '>\BO:?, '1' JUl.. .~ 14 t)() > !) .I. BOll.'~,() ~!~919.4 '· :·) .1. :··; '· • 9 (!'"HH • t> 'J:t.B4.b '· :I.H·~6, ~! 64H4. I) a:HJJ.3 AUG 3:~620.0 1 6~~:~o. o ~~ :l i' :u .• 7 :U.4\94. 0 ;1. :~00(1 < 0 1 :n1n • .t: :~:1.146.~) :1. :?OO(), (I .. :1. :,! 6 :~ ;~ < :-·; !;) E F' ?1. ~~ 4 () > () MW1. >I) L13~! 7, ::! 1.;~:··;()6 > l H !) :··; C) • :·) Yo:·~ 9 • ,, t B::s::so. !) 9 ~5t)C) • () 1() !):1, 0 •. 3 1~NNUf'lL 1156!'5.2 '7:;!00 + :1 9670.1 U4f..B.8 /H:H • :~ 9?4!1i. ~ :1.:1.413.3 7"176.4 974:5 < 4 $ · .. : . ....... ·') . I .· , .. ··. .J .1 l TABLE 2.26 f'f<f.-F'RO.JF."I:T FI.O(II {:T BliNSHlUF (t~'I'H) MODifiED HYDROLOGY YEAA-~. OCT 1 2 :1.6 .11 18 19 2(1 21 •'}"' .: .. ~ 24 nr• .-:,) 12226.0 rs :n. ~L o 17394.0 D~!:·!/,1) 12188.0 .l .l 0 .1. J. • I) 15252,() .l B3'1Y, 0 11578 ,(i J. ~·; .1. ] .1. ' <) LW1',t,,{l .l. <\ ~\'7'1 > () :t. ;:. !j' :';f., • (l 1. n:·i~;:·;, <> 1~i47::..o .1. B?l)il, 0 11551.0 .1.1)/(){;,() ~0524.0 9<\ .1./). 0 l226,1,(l J <\ :} .1. :s > <) :D~8R, 0 J. :1. :!H4, <) ~. :) :~o?, o .l ~)~)l>r:i >!) ~-(I,~.;:·(!,. (l .1. 7~199 '<) ll :~~.~:·1. \t NOV DEC ~i6:S9, 0 ~~~~.t.l, 0 47j?,<> :;r.:o.-t..<> ~·j 70~! > 0 TlH2 >I) 71S'9 1 (I <!{)80 dl ~:i<>9~! ,!) ;·s9?? .o fl:-\.ft(l, (1 4:H:L (I •\:!6i' ,I) ~Lltd > () 7(12~' I (l 41,'(i/, (I iJ () .·~ :! , <) (; .l ::~ {} > () :'i~n:t, o :m•J?, o (; <\ .1. ~:·;'I) •l B~!~} > <) i)~( (i<) I {1 :i!'i04 < 0 6 6 ;') i' , <) <\ B :;! I) , !) ~.(t!)? I CJ 4690. () ~;9oJ, o :~~i:s:·s, <) 7 4 f? ' (l J\ :) :i 6 1 (I ~·; :) ? .1. , 1> :·w Mi , <) 429'.',,{1 :~B:5f,.(l ~) 4 1 J , 0 •I ~·; 6 ~} , <) ,1·1!H I <1 ;:\nB~ (l ;·wlB ,l) :~H4B, 0 'i'Af..?,o 4no~<; 6 J ·:) :'·j > () c)') ~! ~~ ' !) t;(l :lB, <1 l1 <;:~o. o •16?9, <> ;·s:·52'l, o ~w:~n. (l ~r:rn. <~ <~·:~:sH, o ~!7::),1, o 5888.0 !:\28~). {i 1 1 :so , o ~·5 ~s .r. J, 1> %4 8. (i .;:HJ!).(l .Jf:N FF.B V4H,O n76.0 29:~(1, (I :H ;1,::,, (I ,'$<) ? <) ) () ~~ !') J..l ) t) 2B1H~O 2;~4:~,(1 ~S/,61,<> ~~HH9,t) ;1 ')vI (l ~H s 9. 0 :.~td ~! .o nn11, <> lHI(i6 .() ~.4 '11 I (l <\t),~7 '<) :!99!;. > !) ~387. 0 ~(;:)~'. (i •I!) ~j Y , 0 :s ~~ 0 .l , 0 o:w. 0 :H'l8 I (l •I ~~ ·:! :.~ , t> ~s :·s ·'12 , t) 4(1/ •1c () ;~~~? :l I (J VS'/,0 ~~H/;0 ;r:, n I (I :~ <,1(; :.? I (i :H<)4, o ;sooY, <> :~6!Jr:' (J :~~ll)/1 <(I •l J. B:l, 0 ~·SYB.',, <) 26H!J~O j731.0 :.! ,c.,<) •.) ' <) :.! <\ -:\ B ' <) ;n~!:',. o ~!:H,. <1 ·l~!~'i?,O JHi).l,O 33 '12 .(l :?YB·-1 I (l ·:~HB~!, <) ~!~·i J.V, 0 ~J,~i!; f,. (l. :~990' (l ~! ~j () ? ) !) ? 3 :·.i ~j ) <) 4 :n :j 1 (i ;~{)J\ (l 1 (l !I~! .1. :s, o :·s~!~!/, <> ;:,,.1, ~)!\I (l ;7,~!(if,. 0 ;.~t)3;~) I) ~·Hfl..O 2:~n.o ~~<ln.o n'•n~<' ~!~!<)<) '!) ;.)H4 4 , (i :) (; 4 ~5 ' <) VH(l I (l :-~b 7~) ~ {) ;r,~ [HI I (l ~~ <) I'~; ' <) n911. (: ',~ <) J. ~~ ) l) ~.1 818.0 :w ~~; > l) ~!?9;~ I{) ~W'IB, 0 :~(1:.)? 1 (I ~~ ~·) fl ~-~ ) () ~~:~::.l t (i :·~ ;:s ~} :·; , o :! 6 I}{-. 1 {i n~!<>, <) ?B:i. (I I (l :H/J,(I ~~on,<> 2963.0 ] 1 .I liN .IIIL AUG SEF' 23.l1,0 22410,() <l561J,O ~9179.0 54049,0 27/J4.0 3563.0 4219~1(1 588/2,(1 694/410 ~83~~.0 51(169,0 ?~·s~f/, <) .1 . .l ?::;n, 0 bflTW, <) (;l\'~~0 ,() ~i~L16~!, i) ~!~!!)~)7, i) 1\~Hr?~o :w:~(l:?.<> t;4<>?:'i.o :'i42J1.o .1\<ts·~H.o :nn./.<1 ;·s~·!<><Lt> ~s~~~::;c;~;}t> ~·i•Hl!.l~Lt> ~;~s:wb.o :)//IH,o ~!a:·s7.~.o :n:';8 I <1 :H ?~iB .<1 t,9f..B6 I o /M)S't1. <> 'l76'n c<; ;1,~5:m~:;. <1 2~44,0 ~Jl57,0 7J94.1..0 B0369,i) 6YOJ<\,O 4~~95,0 ~907.0 ~114(ll(l 791~3.0 ~23(!~10 ~3?~3.(1 481~110 JJ99,0 27759,0 60752.0 5YH50,0 56902,0 2009!1,0 ?Wl:';, o : .. HJ4 flO I o M?Ht .• <> ~7::.:? :i • <1 n IJ4B .<1 u,n ~~, o n ~w , t> ~~ •lil o ~~ , o :s <,1 :H .1. , o :5H ~!2 4 • o :·:;:·5~1.1. ~-;. t> 4 ]<HI 6 • <> ::d. (j 9 I 0 3 2 4 3 p. <• {I f, (ilit3 {, t (i b ;~ f,/j {) I (l (; (1(-, :u,. (I :;.t, (i/ :t.. (l :·~~·;H .l , <) ~! 4 :··;;~t), 0 lll:D·/ • 0 6 7J~'it>, t) td .1. H .1. , <) :wn .1. ,I) ?025,0 352~~.(1 56629.0 /8219,(1 5293B.O ?9182.0 :.1:w .1. , 0 H6 •\~), 1).1. J..l on, 0 ~'iHB~i6,!) 46:$7 •1. 0 2J~~b7, 0 31!~~;.(1 :r1!'i9/.o :m~BB~o c.::;o~~~.o ::;6:~7!L(1 :);~/n,<) J59H,O 16<\79.0 69569,0 3S~4J,!) (;~00/,l) 30156,0 2639~0 32912.0 66162~0 /?l?S.O R274/,0 37379.0 4J5Y,o J6961.o 7677o.o 697Js.o 46JJo.o 20HH5.o 2~42,0 21~06,0 4934910 4AS6~,(1 42970,0 24832~(1 J150.0 ~5687.0 4/602,0 60771,0 5~9?6.0 27191,!) ;?.(lfi,(;,(i :I.Of,!)?~O /f.20B.O f.4/U'l~(l 74:',:~9,(1 ;~24{1:?.<1 J2l0,!) 36180.0 66056.0 62~92.0 51254,!) 34.1.56.0 2B2j.O 1~21~~0 ~9933~(! ~l?ll ,O ~10B5~0 2523B.O ~~9.1.1»<) ~H1Hb,O 4:\i'.I.:LO :H~Ui7.<) 4:i~!n,!) 29.lJ.tl,t) Jj60.0 2938(1,(! /283~~(1 756Y2,(1 ~16/B~O 35567,0 ;·s ~·~9 4 , o ~~ :.~ o? ~; , o ~j cs M , o :··;~) :··; Ol! , t> ~·i~! 1 :·i ~L o J. H~io :~ , o ;\~'i:~7. (I ?729~~ I (l B77/;'. dl 6:~~~ 94 I (I !'i~i1 ~i7 .o 3~·/19 I (i :i:H~~.O ~!V0/,1) 4BtH.<J,!) !'i/9;~1),1) 4~!J.HJ.t> :!V<1~!,<} Tl(lt\di ;~:~H/t;dl ::iiJH~<J.<i '11J14,0 ~HB97,(i ;u,?f;'(ll(l :.1 t)~S'I7 .1 ?6Ht:.~ 1 ;:~~~1J.7.5 ?--~~)/~·1 ( :1 ~~19?1d3 ?()(ild.' t. ·?.l'~:iB:·~, 4 2f:.~5:'i(l.? :?~~~~~~-1 t 2 2::'·34 5. 8 ?~-~{} ~j l t 3 ~:~ ~) {} '} ~:i i ~} :~~?f,(i I g notd. 9 :)li ~'l:i. I:.!.. n"Y:H. ~' :.!1.).1.19.1 :\/9::i0. 7 :.!<);')9 3. 7 :.! ~}<I<) 7 • l 202:,~:;' s .1. 9 .l.'t ::i • 1 ~!t)Ot)i) I 7 .l ?~HO. 2 HAX 10555,0 90J~.O 6139,0 4739,0 J986i0 JS98,0 5109,1) 50l0~.01110/J,O 80569,0 027~7.0 5370J.o ~7588.4 MIN 9416.() ·· :~97H~O ~?n4-.0 ~?t)(l7~(, l/'3L{l ~!Ol:~~(l :?(l~l:'J.(l H6b.:'i,(l :W:H:tdl A.fl56!'•~0 421lH,(I 1H:Hl:?,(l :i./'~'~i(l,/ ME AN .1. ;:p;)<) , H ~W <\ J .!I ~1? HI , ~j ~S:'H ~L B ~~9 4<), ;·~ 26 :!fL 7 ~H <1 ~L l\ ~!? JO<l, 9 ,<; <149~1 .fl b~~;·!BH, <l ~·iMH (), ~! :.S~!M)b, 0 ?]~~ :.~~·;, 6 $ Tt!IlLE 2.27 f'OST-F'fHJ.JECT FI.IHI ~J SliNf.HINE (c·ff..) YEAR t ··r ..... 4 8 9 1(.) 11 :l2 l:J :14 1 ~) :L6 1/ :1.8 19 21 'F) .-: .. .i... 28 29 ~10 HAX IHN MEA.N i J,lf)TMir~ })l.IH·IF ~ CASE C OCT NOV DEC MAR APR .HU. AUG SFF' 14947.1 1J~J1.7 !J727l4 11638.5 10592,3 9544,7 9014.6 19J94.~ 34034.8 44603.0 4A9A9.0 28714.6 147t7.e 10245.4 10613.8 931J ,9 ao52,o 7992.5 7935.1 3H~~o.3 45189.6 ~4465.5 5o6H6.o 39129.o J. 6 ~~t) .L 0 J. :·wu,, () J.:"Hl'tfL <i J. ~!;·soO, ~i .1. t)!l~! J, ~) 97'/~L 1 ?O.~d) "~ .t 2 ;){; H, ;:) 4 ?9.16, 1 4 16?;~, :~ 4•l,l•l3 ,t) ~!.SB 7? .!) 19377,6 1~i192,9 14196,4 11708.5 10659.5 9828.7 10995.6 46640,4 473A4.8 4143~.6 ~134~,0 27767,0 14619,3 !OOB<i,O 140YJ,4 12557.5 112Q5,5 99J4,7 . 9907.6 29267,5 40290,5 409?J,2 43601,0 24756,0 14012,8 1153~.0 1442~.4 12817,5 11505.5 100HH,J 9i61c6 20299,8 49979.2 53935,7 68218,1 30395,0 14~2A.7 l?J6l.O 1J277,4 11502,5 10602.~ ?720.7 8947.6 2970J,3 55957,9 6J536,4 59936,0 31575,6 18822,5 1502~.0 1502J,4 12896~5 1l7B7.5 103~5.7 9610,6 30964.~ 61001,4 ~7lOJ,5 44703,0 40534,0 ?1969,5 170~6,0 16255,4 12957,5 11312,5 !0154,7 10102.6 ?4605,4 43617,8 44H5J,O 46362,0 2J669,J 13641.9 10114,2 10249.4 12277.5 l1375.~ 9791.7 959B,6 262AR,1 5079~.6 51ROR,H 56976,9 31038,4 lH/01.5 144QH,9 14939~4 1~Y49.5 11511,5 10186,7 96J1,6 31339,7 J0949,0 4J5JQ,8 4J7?5,0 31876,0 17429,4 14l02c9 1~620.4 13629.~ 1179~.~ 10991,7 11812,6 2B9J6,4 43305c2 41l547ct 50316c0 32001.0 15991.7 14651,0 14?~6.4 1J112,5 11658,5 10486.7 !0234,6 212?0.8 6B11H,H 51891,7 52297.9 33250,9 1i'~'i?r .• ~. Hi}46.0 14806.4 1:296 11.:·) lt'i':P,:) 9~'10,7 fi7?1L6 3:1:'if)/',;;~ i.j(t~)?:'i.<t :)B96"l,l) 44414.6 26lb?.<~ 1VH83,9 !3901,0 13649.4 11bH7.5 1076J,5 9524.7 9034,6 10J99,J U6584,6 4J77J,J 419J4,0 22YY~A~ 1~472,9 11639,6 11003,9 12070,~ 11?78,5 10329,7 10138.6 2l342c6 ~2237,8 4697Jc5 47253.0 47839,1 21778.5 1JJ13~0 14081.4 12294.3 1iJ25.3 10386.7 1~301.6 1444J.9 5~!05.7 4J644,6 52177.Q 277~6.0 14003.5 9597.6 l0340,7 12588,5 1j610.5 :1030~.7 9342.6 29498,6 4H2B7.B 60697.9 728~1.4 32439.6 14276,5 13406.9 14679,4 1JOJ1,3 12J02,5 11409,7 1!062.6 3J520,5 5HH21,B 5JJ57,6 41560.0 21369,0 12833.8 9457,1 9728,0 9441.5 10047.5 9533.7 9143,6 18622.9 36691.7 37323.7 3H64Ht0 24336.0 ~.:~?:!(),a ?/6!;.,:) n94,'i niJ4,~~ !J"?ld>,:l.. H.P6>il 7Yf19,fl ~~1~)/~1.7 ;~H.I.H:·;,.'i 4/lt)H,t 1\6946,1) 2/:~'lt),t) 14467.4 1176(1,8 11121.6 9~64.2 R155.7 8248,7 764~.4 1~296.6 5376?.0 4HB99.J 55758,0 27262,0 ll194,[ 14lJ8,9 15038.4 13147.5 12117.5 10846./ 9913.6 32424~9 49017,7 472.t4.0 4J964.0 ~1056.0 14983.8 10629.6 l4146.4 12202.5 11300.3 10157.7. 9524.6 16186.9 41047.3 39945.0 42795.0 ~5464.0 1400H,O 9917.5 102!4,6 9187,3 8467,3 97J1,7 9619.6 2HOJY,J 33791,9 J9949.9 J9002,0 26164,0 1~114.3 l0?46.3 10311.7 9604.4 8238.3 8305.6 7687.8 23054.5 54016.5 59052.7 45588.0 28557.0 17642.0 12232,0 12950.4 11397.5 10671l5 9792.7 9997.6 19023,3 41JJ6,J 4J01H,6 44355,0 19671~5 j3474.2 10589.4 112?4.5 10018.2 8668.5 965J.3 10246.6 24217.2 68864.3 47232.1 47917.0 '9379.0 17297.2 1J672.7 !5429.4 13103.5 11543.5 J05!J.7 10245.6 19426,0 35610,9 44153.2 37728.0 23t35.0 1~330,9 10387.0 10746.1 97U2.B 8457.4 8339,7 80~5.1 29816.6 4~067,0 54601,3 40437.0 253~0,0 21969.5 17026t0 !6255.~ 1J629.5 12302.5 11409.7 11312.6 46640.4 86594.6 6J556.4 72831.4 47959.1 12833.8 9457,1 972Ri0 · t187.3 8052,0 7992.5 7649,4 10399,J 30948.0 37323,7 37128.0 19671.~ 16t)7b,7 1~~;}67.~! .l.~f02~!,.1) U7Q:J.7 1.t},1)()J.,·:~ 9Ht)7,9 !J~j()(),t) 24H9fL~! 4BO.t.t.J. 4n:'i:H.4 1.)7"/69.6 :!9l.~!"i.7 J J J f;NNt!f.:J. :H•}60.9 ~!.~Bf., t, 4 ?4B:~4. 4 '?JH/3,2 ~.~:)6,~· 7 .. B ~7::;f.JJ t 9 ?l,!i~,o, 7 ::!~~~'j()9. 9 2 -166('1,. l ~!~!~n. 7. 7 ?•l99~' •· 0 :-!6~Hl3, 3 ~~~4!H, l ·~!4~·!713. 6 ;~4ll~?,~! ~!:~:·)~:19. 4 :?69111 .5 :·!<1992 .~, 18879.2 2<)719;6 ~!4\H1.2 2076!).:;? 19n4. 2 ?:HH~d~ ~! .1.1 ~i 9 t 0 ~··H67,/, ~!lt)94. 0 ;nntW.9 n:Hl3. 9 1 BB79 ,.1 l 1 TABLE 2, :w PF:E>PF:O.!ECT FUltJ AT SUSITNA < ch;) HODlFXtD HYDROLOGY YEAr: 1 "'• ... .. , ,, 6 ? 8 9 10 11. 1. t.\ l .... ,) j,;) l/ JB ).9 ;'0 ~t 2'7 'Hl J.U OCT .1B026,.1 :~:to~·.:~.~ i ,s 2389:;. 7 · ~ '!9?:L 4 4tB21.t, :·.i)6:~,<; '() 30~i4 3. J : .. ~ ~··.i '? ~j .\} ,j J .1. J :~b? '.1. .Udb~l ,H 1 /:..2f:S' t :t ·'· .I.W?I.J • J. S'tf..l,fl J. !) :i ~! .1. ' ') :? t ~· 'J '? ' ~) :t ':lHBt.•, ,1, .1. t) .l .1, :) , ;:; ~~ :! 'j' J. ·1 \ :\.) DEC .lf.:N fEB 6197.0 6071.9 5255,5 ~980.9 7073,6 7294,9 .1 'i fW , :·i fl ~~ l4 , ;~ ? 0 ~~6 , ~~ 9746,0 806H,7 6774.5 5271~6 7202.0 4993.1 6183,0 72~4.6 5845.1 7294)1 6179,2 6830.9 14l~A,3 10600.1 8356.1 .1. o . .~~~5!)) J /~l~-v~~) 9 6]Hb i? 4763.4 779~.1 6564.3 /(,fi).:}>,'j /t'?l,~.~~ 6JJ.(),t) 13768.2 12669,1 10034,0 ~?')':):):·;,? .!. JO •IJ, ;·{, O?l,i.,, l1 YO:)O, .1. 6.lH:~, ~' ?7716.2 107~1.~ AB6~.6 8610.7 7053.A .~ ?B"\ t:• , :~ J . .1. ?OJ "~ . ~·i,') ~·! b, i) .~=~~·)::. , 1 :rl t:. J. , 6 ?8746.9 10458.0 6126.6 h95j,9 6195.8 ·.~ 6 ~·; ~; .~ , ~~ .l :~ :i .1. ~,~ • ~··; Y :1. ~·j 9 • :~ n Q .1 o , B :t 4 a 9 • ·'f 26396,2 1296?.~ 8321,9 BO?H.~ 7726.1 37724,5 1sa;~.a 1~oat.o 11604.~ 11532.2 26322.5 1108~,4 7194.5 6924.0 6163.5 :~ ? f. tJ J , ·•l (.? 9 ~l , J ~51) .t. 6 , "l · b !) ? •} , ·~~ r·i :··in J. , :1 3291713 lhh07,2 8lJ3,? 6508.7 6253.8 32763.2 149)!,1 0790,8 9379,7 8~5H,J 26781.9 14B52.9 8147.1 7609.2 7476~7 ~~ t) •n ;) , l J. n J. D , :~ ,I; 0 H 1 , 0 '? ~ <) ~ ,.) 6 7 .<} 7 , ~~ .19~;:w.o 104oo.o 94l9.o B~:i9'l,() 7tHI-'l,(l Jl~50,0 99JJ,Q . 4000.0 6529.0 5614.0 30140,0 18270.0 13100,0 10JOO,O 8911,0 J32J0,0 126JO,Q 7529,0 6974.0 6771,0 3681D,O 15000.0 9306~0 DH2~,0 7~4~,0 /;~~B1 • ~ :·)wn, o 6347'. 8 4979.7 531 ~·i. 6 /)::$~~4 i {} n~:d.t b.';/1),}1 5lo~t,:.) ( :.:t I'! 1 r: .• A • ,t ('t ~~.J ,1, ~ ., :·) ') ~·; !) • 6 l,(>:'j~~ •. l <: ') .1. i) > 4 f>J/.:.9.?' /!)'))\) '~) 6683.:? Hi'??,!) 5~:·· ~ ~) { :~ ~-) :} ;) J. )' .. ~:. ~.iHB2 I f, 61!4:··; ,H f,:~:i,;~. 6 6~~9\~ ~? i'04B~o :··; :lMl, 0 6774.0 Mi90, 0 70'!./.('t APR. 71'9:}.{:. .~:·so ~:i , :·) f,l}:l,2,t{ ??0~.) ·, :·~ B09f·~ ~ 6 j Hf.:Y .HIN ,JUL. AIJB SFP flB})4(l, (l:i:W:)f..:i.' :H~,~::.CJ49.2 97{11.0, 0 4416? I'/ ~w :·) .1. 6 , 4 .t tHlfl o .1. , !) J. 1. ,~;. 1 ;~ J. • ,~, :t21l ~w .~ , 7 b .s :.!7 ~j • ;! 58164.016~041.814887~.512(11201(> 53~0412 B ;; •l B ~·i , B .t (, :1. :14 6 , .l .1 •• ~!I~~ .1. 4 , 6 .1 • .l.l. .~ J. 'J , ~j .1. <) 4 ~! J. a , •l 6 :~ ::! 0 ll I 41 'J f.? j H I fH 4 (J :~ 111 I :~ 1 ~~I! fH :! • IJ H 'lH?:'i ' (i ?.:):\?0, :d . .1. ~i~J9,) ,fH~!~!:!(it), '? '/960:1 ,fj !)~~~)~·;~~ .:~ :if.t.{H. 41 1 060:? I :~:i.'lb21tl' H:i.:1B:B4' J /..}')(!;~. !) 50061.~ H4134,4129403.411J971.6 BJ.565.4 f.:!'i4 ::;(;, 7:t :; .tn ::; . u M:~'r.n I ::;u 66%, ~) i~·~':'i04. 3 6635.~ 545SJ.H!6J049,01414~1.3.1.2l220.5 74906.4 5564.7 5J903.2 85647.91464~(1.110670618 ?0182.4 ~-;~)~~~), n ;·l:·i:··;:st>, ~~ .1. ~j:·o. ~!,(,. 4 .t2,Hl0:5. a 9nn, ~i 46~ 1)9. B 7120.1 494B5.4110074.613R406.5111845.9 R99~A~3 HO 1lH >] :·):! ."l J . .1 .• 4 .!.~!~) ~-B~! > H .1. J. 7,',.()'1, •11 J.li/~!9. J 6]BH7 > :1 7280.6 5B106,6134BUa.Y1~6306,J13731B~O E95?7,0 Hi' b ~~ "'i <; •H >\~L :.! .t.r/B,) 7 , ~!.1. :~!)~·; J .• L 6 (·lM17 •L ~) 4.nti4, B A112.0 52Y54c0108336.2J1554i'~9 97076,0 57771.6 5769,1 5JOJ6,2 94~.1.2,11329R1.7.1.1772H.O 90584,9 :r7H'l, t) ~~98<t9, 3 U??~Jt~. n ~ s-J. H:r,. 41 :~?.:H o. l 1, 9<,~? :t • :? 48'/4,9 74062,0.1.7602J,91427R6.H1Q7596.6 60~?0,4 ?M:H~.2 t..453t1.01n?97~11~!;~;~62,;!HI7:!o(l,~~ 4:5~?::1 6,8 6962,8 ~1457,8 &7H38,QlQ~184.J 9025.1..5 56123.5 6867.0 47540,012HH00~21J5700~0 913A0.1 777~0.1 7253.o 70460.1I07ooo.ot1~~oo.t 99650.~ 49910.0 623~.0 5618010163900.314390(1(01255(10.1 83810.1 7o:s~s, !) •Hlll ?ii. <> ~!O't :·)!) , (I ~.176!)(). 11 o ~! .t.t>t>. ~~ 5~i~5!)!) • o 8683,0 B1260.1119Y00.01~2500.0128200.0 74340~0. 1.• •' '1(.''7 •' ·,·J.' 11\1-l J 1 ~,~ H ~~ ::; • ··1 It f.)::; :J ~11 , ~.1 4 ~-; ~~:' i' () • 4 !H ·1 :~~·, 1 ~)9 }1.)1 I 9 58911.9' <llfUO.l .!J S'flOif. I 5 .<).~J./2.5 5!HU.,? ~)!U99,() 4 :i. 1/7'9. 8 ~ ~~ (} t 4 • 0 48289.9 ~).nos. 3 -'l~)-1:.3.5 36~~85 .1 46.t.O:!J <L~OH9, 2 . ~)~)~)?;'' :~ 4 ?t)t)2. 4 ~5:~676, f; MAX 52636.0 21547,5 .1.5091,Q 12669)l 11532,2 91?2,6 9902,6 9414J.~!7621B,9!611314.6l38334.J104218.4 59701.9 MIN 18026.1 6799,3 476Ji4 6071,9 4993.1 4910.4 5~J0,8 29eOY~~ 67BJH.010?l84~3 80251,5 39331,2 36~85.1 HEAN 30401,0 12807,7 3JJ.l,B 7968.9 /071,7 6332.3 69A7,J bOJS0.5124534,313237?.5111V97.7 66752.9. 41!307.6 $ HlBLE 2,29 POST-PRO,IFCT Fl.fJ\r1 IH SI.I~:XTNC: (cfH) . ~hH:·\N}) t\I..OtH-: l CASE G 1 ') ... 3 7 a 9 10 u 12 u :14 1:-i :16 17 :1.8 1':1 20 21 26 27 n 29 :30 MAX IHN MEI)N $ OCT NOV J.tff! JAN FEB f.:F'R JUN JUL HEf' 27814~1 18999.8 16313.4 14962.4 1J572.0 12888.4 12360.5 ~3270.1 90037.3110313.9 70551.8 40311.8 2056?.9 D,~M),;? 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U~?3:-i.4 :i.~'H-l/l,(l ~t3412.1 57:1Lf! .r,r.-·'}··r (\ .. _,,,,·.:~~> ·• 1~11.~ o iiJ·~: f.: <J-:~·t '1... s .. f(.,~~!.'~ ·J,,~.~(I."J ·rn·{·\<l~~'l ·'.)'a({\ .. )% .. ·:t ~:)l\!~lt\ .. 1 1~~.!.'.1~ .. ~~; 1(~79~> .. () fli·~Nllttl 6618.1 7733.7 "JTJ,~.'7 803!':1,? 71<)0.4 8:7:1.9,;~ · 90~'!1 .0 fnst, o i'?fi9. 4 8<i11 'ij /9:~;4,0 'iH;~2.9 ~nn~? ~i~~ 6 2 t 7 8>151. 5 J:P4.4 f.10(l. '1 \~ .l.l4. 6 B!:iBB, ::; 8~'63 '4 /U~~ •. o 6 . .H3.7 B4(l:~: I'? Mn4.8 6992.2 8183.7 89()7.9 9:'i!Hl • , 9fl~2.9 (:. :i. (l(l ' ·~ H1BLE ~·. 33 PRE-N~tl.tFCT FLOW Al TIEVH (:(.tt~Y(lN < d'!:) YEAR '') -'• 3 4 "' ,; 6 "1 l 10 11 u 14 1.5 :1.6 17···· )8 19 20 21 24 """ .i-··-' 29 :30 31 11A.X ... J MOlHFH:J:t HYDROLOGY OCT NDV ~'i/~)H, ~~ ~!40·'l, l 31:.52,0 ~;(::D, 2 ~;;!n , ? ~~ ~j:Vi, l} 7517 ' 6 ~{ 2 ;~ ~~' I> ~·5 t l)f/ •• ~ 1 '-n .1. , :~ 4 830.4 ~?~'l()f>. 8 .H!)'/,9 l/HH,.~ 5235.:r. nn.F:: 7·434 > \'·~ ;)~·;9l)' <l 4402.B 1S'99.8 MlM, 1 ·u;:??, l ?170.9 2759.9 ~·;4:')1) '4 ·;)~·).fl<\) J 6307.? :Nst.. o :'i'tS'8, .~ ~!O:'l!'i, 4 57 4 4 • () /. 0 4 !'i ,. 1 o4'i'.~. ~·i l'io?, n 3844.0 :l4!)/,9 4 rjH ~·:, } ?) :-~ :-~ o3 ; ~·-; :~9n .. o u8:1.. o :-~866 I ~j 1.1.t.l:'·j > l 47t.1S.~.1 30ti~,fi 5!);:p ,() 29 J.2 ':1 4638,6 215-'l.R .r.·t~~·:~ ,4 Ht.~~, '1 3~106.8 1619.4 7()();~, .~ l H~j:~, I) 3552.4 ~·?.91.7 6Y0\~.~~ ::S~~.l<)dl 4502.~~ n2.<1 •. :-s b 9 o.)!), t) ;~ y :·) ~) ; I) 72.<16. () ;1f..9Y I (l nH 7 "') :·~ 9 :··; :L !) .JI~t.6 .... J 11 • .... } 1.1EC ~o:w. F:: t /~):7 ) ~) 1 ::<~:.o. 4 DB7.I .t s.~s. (i :l ~~ !)(', • ,1; 1986.6 ~~')() 4, 9 13?0.9 ~~ () .1. :t. , ~i li.U(L7 Ul'N,.(l :t:W/, 1 Hf>{), 8 :1.47:1,1 1 :~t'.4. 9 l ?:-~'J, "I 1.23?.0 Hl!), l) 2074.8 ~!:U ;! I 6 :t:~87.() 997. •l 14t:f..~:i 1 !)()7, (/ 2H7.~) nn., •l 1~)49.4 ni'Y. l L} 1 :)!':i4' () :.~')!) 4) 9 ,l.t.-.., ,Jo 9:H , :~ /~S~:i. 7 ~-('l ~I t 7 7 6 7 > ~j l ~ fU , "J 9 tl :~ , ~! 999.6 7·15.;', ~n~l.~! 9n,; 9V. 7 a•n, ~ :t58:i.2 13f;8,9 ~ 7n, o :t ~! :1. :-!. ~~ DH.9 U7Yd. 16\if>. ~! L~40, '?. ~~:.l~ '},(I :t :5~\3. 6 11% ,() :1. <) .1 .• L 4 l'i'J.l.,(l 1Ml7 ,4 lJJtL !) <JI)(). ~! 9~:''i.3 8?8,f.: 1~!i'H.7 J . .l01,4 1357.9 1?68.:~ 1fl!H,·;! :~.nB.l 1(1 :t /.' • 0 f)!) 9 ' (l n·if.,9 7Ml.l DHl,f:l 94~.6 ~!<):{b .:t. HJJ6. 4 1B9.8 11/.B,f! 84~~.? /4:L9 HOH,8 D42.?. H96 .:~ :-1/6, ~! :t ~~!57 , 4 H6 9 • 7 1867,9 .l~)~!!L 0 DO'\, 1 · 12<·,::t. f, 1 6 4 9 , o 1 :m.L c> 1287,0 :I(IB9,(l ~! ?. 1:-! • () ',,J .• 9 HlMl>4 .I(IH, , MAF: 6"/l) > 1) (:.97.1 l/;6 ,. ? 7~!<; ) :j J. (I~-~ :i • f:, (-} !'} ~! • :~ U(!!L 4 :t. t)fl:"j > 7 0/i',lf ~.l . .l.~~.H H,:Hl. 9 n~>t>, ~~ 958.4 6/!:L H P,{,l:,. 9 UH7.A 10H!f.~ :t!f(L? /IH1, (l 1·;~1 .a 866.8 1.~~59. a 9!):l.() j;)C,j,(l Hfh), 6 1;1.64.7 ~-~~~!1,() 91)7 .(I APR ,JIIN .lliL RFF' fit);~.:-~ .l.04':.1t),/ Ul·1MJ,6 2U8:~.4 UHnt),f> '19~)t),a 1504,(> 13?18.~ 19978.~ ~15?~.9 185~(1.0 ;1.979¥.1 SJH,5 4909,5 30014,2 21861.7 19647,2 13441.1 1:5:-H,.Il J77~:;g,;~ ~~:)n0 •. 7 H'jB-1,(> 11J:W/,(l ~~~9;.lfL-1 1.1.30,6 15206.0 2J1H8,1 19154,1 24071.6 11579,1 1107.4 R390.1 ?R&B~.9 26212,8 24959.6 1J9B9.? B67.J 15Y79.o ~~1~1.1 292t~.o 2260Y.a t6495.a :t 1 o9. o 1~.~J. n. 6 2H41 :) , ~~ n :i. o!J .6 j_ 9JB~'.? 180~1 9. o 1137.4 11D49,J 24413.5 21763.1 21~.1.9.8 6988,8 1119.9 1~900.9 21537.7 23390.4 28~9~.4 1~329.6 1 :! .1.? , (·l :t. 4 a o ~~ , 9 :1. <J/' I.) 9 , s ~! 1 n <J • :~ :,! ~·! <M 6 , 1 HJ9 ~~9 • 'J 2-40:';.!1 ~.t,():HI,/ :U%9.~~ 228H(),6 ~!1164,'\ lnU-J,t, 1613.4 12141.2 40679,/ 24990,6 2~2~1.H :t.476J,2 810.9 17697.6 ?409~.1 32388.4 2272~.5 11777.2 696,~ 4046.9 47816,4 21926.0 155H5,9 8840.0 13:t.4.4 1?267.1 2~110.3 2~19~.7 19/89.3 18234.2 1619,1 R7J4,0 304~~.3 18536.~ 20244.6 10B44,J Hl:\:~.7 :14<1:-l!'i.~) ~!7796.4 ~?:WB:l.~? ;~(I:?IJ:~.01!)'n8.:? 1791,0 14902.4 29462,1 24871.0 16090.5 B22B.9 959,(! 9151,0 :194?1c0 :17291,(1 15500.0 9;1.88.0 10~6.6 10721,6 1711B,9 21142.2 10652,9 9443~5 98~.2 3<12/,9 ~;1.()31.0 22941.6 30315.9 13636.0 1565.5 19776.9 ~1929.~ 21716.5 18654,1 1:t.HB4,2 986.7 7WN,.4 2fo~J,)'2,6 P!J/1,8 H'lt78.1 H/2f>,.O ~'-'l'i..l :c:·)<HH>I} 167M./ :1.77'i't),O 1~i·;!~·jJ,Q U.J'l0.1 1.4~)6,7 140U,.!) :H;;-so:~.6 ?.',:t8R,O l70~H.6 J:H:)4,"/ 1~61.2 11J05.J 22313.6 18252.6 192?7.7 6463.3 1~09.8 11211.9 3~606.7 ?1740.5 19371.2 11916.1 1597.1 1169J.4 18416.8 20079.0 15326.5 8080.4 1402.9 13334.0 ?405?.4 ?7~62.8 191(16.7 1(1172.4 1575.0 1J.J7J,() 26255.0 ~0()02.0 201?6.0 12342.0 123a.o 11676.0 l771t.o 31?36.0 3527a,o 1/.762,~ 1 ntL? ~!4o:; ~ 4 l<JJ!b. a 4i'(H 6, 1\ :~~!1~10. 4 3~~~!i'~>. o 19799 ·1 · J66:~.,,J 6~ ...• J 3·''" ,,. l·Tn.-•~tB ut9Lv Ji?.5rtv J 6410••"}f,,) f:NNU(.:J. n·;:n, 8 Bfd ~~, 9 fl'Jl. 8. 0 9~56.4 (·l8M>, 9 s·J<I7 ,.A ~t)/,!)S. 2 9668,7 SH66.8 9/.-19.6 9(iB4, 4 1 (l(l?l • ;) li)'/46 •. 5 HH::o, B y:.!:;;o. 7 HMi' .o 10460.4 9l/::J. 4 680(1. j ?t).s:~. 9 %~i7 I? ~0:1.99.0 7nH. :' 7:160 '5 9606.6 94;{8 ~ B 77ll'5t1 9023.0 ·~9'14.5 10577.9 tt)9~6. 5 ol:•~() •) l ) 1 h'IBLE 2.34 F'OST-F'F~O.Jf.TT Fl.fJ~J f.1'f l~f.:TMU: (d's) W~HMh\/flfiJXt C}\HYI)N : C:~SE C YEAf\ 1 '') .... 3 4 :;j 6 ., ·' 8 9 10 11 :l2 13 l4 15 :l6 17 :1.8 19 20 •; . •'. l ... ~ J'} ..~.:...:. 23 24 ., r:::- .t.·.J 26 27 28 ?'I . 30 31 :32 IMX ~il N 11EAN OCT NOV ftfC ,JAN FFB 5564,1 104~5.0 12314,6 11139.4 ~0785.8 H70S,4 11900.0 .f,9AB,4 '79·~~ .• 1 n4S,6 ,1~~77.(l M!1L7 90~1.1 9950.5 12276.3 11~01.1 11021.6 9708.1 9261.1 109J6,8 12249.2 1140R.5 1100~.3 90?7,2 ll4??)•J ,!.,J·:lO~tj .I.J.~)Ht):-.t J.llO:~)~l .f.tJ?H~?~·t H?;1 }:·~··; l0208.6 6683,3 122~0.4 11316,7 10961,5 10315,6 /07/,7 1tHLt.l.,9 :l?~itl.~~ 1l4~·i:5,6 1.t)T\.:\, .. 1 (JH~L·),} 7183.4 10907.1 12?48.1 11394,9 10~67.3 10193.6 080~.9 108JO,/ 12128.6 1131~.9 10942,6 10208.1 11673.8 6809.6 778~.9 9626.1 10928.8 8833.3 B J. 'l t) , 9 J ti 9 =l ; , ·~~ :l ? ? ) ~~ , o :l :t. :·s b ~> , :·~ :t. 1) 'i r) l , •:> :r. () :) o .~ , 'l 10336,7 10068,4 12172.4 ll373.7 11003.6 10175.? 9420.4 9619.6 12J47.a 11410.3 1099t.t> 10209.5 8535,5 11048.4 1?289.7 1140~.4 10966.2 102~9.9 H162,5 11~12,9 12J05.9 11412.9 10999.7 8714.5 10477.4 R75H,0 123~l.O 1149?,6 107~7.5 89~6.6 8196.6 10791.1 12267.8 11399,3 10978.1 96~5.'i 11738.4 6814.9 7793.1 9300.0 1101J.1 9028.8 .~ 9 '>1 ·~ , 4 .t. :1. 0 .t.l. , !) :1. n B 6 , ~t, U. 3 r~ B , ·,~ :1 0 INd. , ,~ l (H 70 , <} . 11765,1 ~839.6 783~,0 8575.6 j0727,R 88,5.3 11900,7 701H.2 HOJ9.4 7~19,3 ~448,0 6~91,5 ~~ ~':i (l ~·j ~ 4 ?~)~.3o6 ? ;·) ::.~ :1. ' .1. n~:;~n.l 1)1~. 9? :· B 748B{S B,<,J II,.;~ 9{r7 ,~, ·1 i'? ,1. ~! > l) ·-1 t:~ ·1 r.; ') ( \} ! -· '.• {" ,.~. ?~. g:··;,) :) 7<1~i?.F: :··;! ()!) ,. <) ;) <) /l) > :~ 1. ~~~~ 1\ , :1 i~ 9 ~~ ~! ;. ~·:i ?<<?tt < 0 I. ')0".' •') \ ~ "· ~·.,• .. :· ,; ; '1 ~j ~j() ( :s !.dW .l, :1, .~~ '/8::._) (? 6 f) ~'j ':} :· ~'j -~ {·j}f~ t :~~ /~'·j()J~6 n.?n. J. /U:l:.,B ~) .1. !} ~·~ ~ !) ~; '? __., ~? I (# '~ ~.')66' .l. 711!-<\,~. /2YH>B .{~~}if. ( ~:; • .I liN <)i) J. J , 0 4:·!8:L 0 :s .l 9 ~~ > fl (;,2j~,~i4 ,·~~~.t~~ ~ t !'·; ). t~ :~ t 4 /.~ J. J. .:l .' (J ~'j /• :-~ ~') ; 0 :~ 4 :.~; ;;~ ( :.~ -~1 ~~ / ,··:. } } ~·· 7; t. 9 i· ~: !':; / ~"~ :1. )' {~ ,~,:~ / i' t ~.) ~·:: / J,) / } -:) !)~-~·?::' ~ ~1 [; ~·; ,•. :) < ? 40/9' l i' 9 ~·; ·L !") .1. 0 ~~ n ~-;, 4 J. n!) 9 , ~) J . .J. ? S; ? , 8 '· t,l (M 9 , :··; :1. () J. ·;! .L ') n ~·i .!l, ~! .'i 4 (; :L .l :··; f.lJ. •:J ,J. 7715.4 10748.3 12329.9 11451,0 11014.3 9396,7 7~1A,9 5072,Y 4338,0 u a -=J 4 , .!1 t) ·n ~-.;, ,~ ·n ::w , .1. 1 :n ,"; , ;~ t; ;o· <) , ·;! a o o :·j , 1 7 ·'\'? :i , :~ ·1 :rn , n •l o ~l·L 9 11900.1 69'/.1\,~) n'li •. 4 n:~l!.'i' ,•.:cr7.o r·'l~j$',B ~i/)((/~7 ~·;;n(;<J',r.. t.~~o8,3 B.'.·~·i4,:'·j ~.lW?·:i,IJ 11801.3 6i9?.] 1 !) P B "~' :1. 0 <) L! , 'i 11.n.e.o nBA9.o ~. :1. b "i 2 , ~~ :n ~::i :·) , 1 9433.4 10950.5 1~3~3.9 11?17,3 1072J,Q HBXO,O 7?7~-:J t 9 ?2~)7' :!· f:. ~(/~? i () 88:):).( 4 1~2!)5.4 11359.5 109~!).1 10167,) 790J,9 732:1..9 6356.0 6~19,3 12272.0 11411.6 10992.6 1!)207.3 12289.0 11~51.9 110~3.6 1~223.1 l.l9r.)•,), J J. :1. OA~L 4 U::i(·l6, ~i U. ·:)97, 6 1:1. t)~! .l, 6 l i):H :) , 6 5564.1 6683.3 7775.9 7~2J.3 6272.0 6459.8 9764.4 9112.6 10881.2 10~87.5 9124.6 9059,~ ;'6b;:~ ~A :} :.!OH ;>? 7i,::oi~ i :::~ ;1(;/? « .s· ?:1. iJ9 '9 (;~)~) .1. > .:) ??:3~{ t 4 . 7();~~:t r !!j 'i (){).!) , B ~·i l) 0 .1. , 7 ?~.'!9,'1 f.i:I.OO.<l 1793.? 7~·;o.t, 6 4(1/: ... ) ( f;• !·:;n~~b ~ b ~~J ~;! H ~. i ~) ::} ~} :) ·t ;. ? 6l; ~·~\~ l' s~ ·1 64 ;~> { '.i' b6)l),9 ;•nc;n, 6 ~) .1. ~~! ,~} :. I> .I tiL :w~}~, o .')6~~B, 9 :·u:N, ·J ~·):i.?B,? ~··_; ~1 ~-~ <J ) H JB~)·t>H 3·1~?! ~~i ,'iJ9t), a 4:1 Ol•, ~.1 (; \~ ·.:.~ ~ 1' ,tj ~:;/:i'J ( 0 l 4 1)(-)l) • 9 :~~'9-1' () ~j :1.? t) ' :1. "'T • ., I •"J () ,~!-l f.• I ( '~' ;-s-:.! ,) .~ > •) i'O:~:;,;S o ··! ·l ·r "f 1.' i' "( '~ ~ . ) :'il?~~B :} -~ .l B '•.) ~)7l)0 ~ ·~.~ (:,F;iJ~~ I/ C'HJMl,6 8 ~j~'7 < ' -,r:;,~ "I I ,,1 ... ,~ \) :1-I .. w:~9 I 1 ~) .? .,(~ i) I ~) 4H':?,;; .n:.~:~.? J. :~46(; < 0 ~-~1:1.9~,·:1 8'.!9:1., I J. (i 1 !j 9 ' 'j' t) ()•.) ':i' ' ? ~1 H() .. ~ i {~ ), :,! ? .:\ /:. ) :~ 1 (lBOO, () ~499,0 69~7.4 51hJ.~ ··1~;i!l/,\ :'ir1(<~!..:~ J.()l!!\/,) ~h/4,0 3623.9 4935.~ -~~; o? n , 6 n ~; 1 6 • :~ 1. ~~ rl '7? t 7' h1~i.6 1013,0 ARHO.~ 1:1.1.n.o t!:n~i.;:! 748:>.~' 8 9~\ ')I f.. A512.3 7.l1H,4 92l3o6 ~?30.3 43Hl.1 8325,7 3978.8 1185.~ 6234.h t-1.1\B,o ~'ib:l:~.o n:~f .. t:. rl )~~~)-~ ':/ f~ !: ,f:. !') ·' B <) •.'} :~ 7 ,. {'! /·.(14 :i. ' :$ !·i 9T,~, ;1 :·:i(lU ..1 l~6:~!) •. ~ ~4-1~~ 4 ~~; ~)~~?6, .. ~ n J. .~o: ~·:; n9B:.,7 ::;t.m::,:! i)!)i' .1, H ?04 7, ~~ ~)(I]~~ ( ~\' 4 ~' / j, I S' (,6!')~~-~ ~? /()3 '4 ~ 9 ~ 40 <\~. 2 t :;;,t, ?';~ > ') :n6:1,4 4<109,:~ ~) 9 <) 7 .. ~) ? H ;H} , t} /:-:;1_;~.1 {-,f.lj'' ,., B6?8, ;:; ·:,)J_)~.)l ~ 0 •:.·~.'·.~.·~ i) 'l.• .. •,.: .. j; .. t~· . ~ .:. ;··, '' I •' 1. I ' .·~. t I 8 ~~-·~A i? f,9"](! ( :·~ H?68 t·7 9~j.32 ,. ? t;.:;)l~:~ ~ H . Htj} 5 r l TABLE 2.35 POST-·f'RQ,JFCT FLOW AT l"IEtJH Gf.:NHIN (cf£.) YEAR 1 2 3 4 "' .J 6 7 8 9 1.0 1.1 1 .~ :1.4 15 16 17 18 1'/ 20 21 23 24 l4Af:.)J'!~) /D~:tJH. CMffON : CAHE C OCT N!W llFC Jf:N HB 660?.4 J075A,1 12408.~ 115'/4,6 10R79,H 3009,3 12252.9 707?,3 R065.7 744~.3 ~471.5 65H~.o (j·t; 'h) , ? :1. 1)? J !) , 4 J ~: :·:; :·~ ~! , B J ~. /; .1. t) , ,4., .1. 11 ~! ;~ , H '/B l.i .l. , ;:) 10493.0 jJ39?,6 17~1~.4 11589.2 11137.2 99)3.7 12368.~ 7062.3 1178J,1 112JY,S 10909,5 HH~B.7 11179.8 7139.0 12568.9 1:1.63?.5 1118~.2 10453.1 7623,3 .1.101~.4 .1.~405,2 11560.4 10B72.'l 8991,6 8210t7 11404.3 125~7.7 1160~.1 11167.2 10364.0 :1. o :~ o ;) , ~i .1. :1. •lB :··; , ~! :r. ~! n !) , !) :1. ~. 6:? 4 • ~~ ll .1 . .1. J , :t :t l) ~Q l) , ~' 1240f3.6 707'i',9 fl(i3'1'.? 9.Bt,:2,(; 1U~d~,<;· ~·(!17,? ? •lll J > ;~ P,DI\.6 //?.3.4 7'/1().:~ '/ -~} !) , .\ B7~~6, (t 7'7??.7 (:.~~()~:i 'l) 11 9:i.:L 0 ~1? 6r~; ~ !") 91 ~)(). :; YH/1!,4 JUN ,',I)~ 'I , ~j ~)? ~~ :~ I 6 ?:D?.4 99H(r{~~ ?t)'?,'} ~ ~j r~~~~:t) ( ~~ n:~~B:~ ( ;r 990/,l) .l,!)r.)/'),~~ n:.-?.6 r.nn,k ;-~~:··;o, 9 79-~(), '.'! Hl,~:i!L :•; ,',.~~0 I 4 JilL ~999.5 5987,9 01/7.1 57j1,J 6046,0 953?,7 63'/9,7 7461.0 76~0,4 5760,1 6293.2 6607.4 ~9~0.4 6914~1 65J7,B 755~.6 8~38.2 13007.~ 9210.5 11699,7 16~95.0 !) 9 ;~ :i I ~ 7 :1. 9 :•, + 3 :1. ;:.-:t '/ ~· I 6 5865,2 67?4,4 AB63.~ ~339.8 10201·2 1~01~.6 (; 1-11! Otd. rl4()1,B l-1Y'l',? ;"-!91. s ,. 0 . ~'.Ji5l.\ ~ 0 s· 61 ,•., r-. :1. () .~ 0 ;:; ' ;:! J.! ·r ""CJ ·' ,• '·' 'i' !• ''i ?036,1 11J56,4 1~561,2 1164A.l 11168,3 :1.0355,1 976/,2 ~?60,3 5749,6 ~OJ\,0 6~~3.? 685~.:; 90~4.8 11458,3 10500,~! 12f..-,l~) •. f.! U80:-i.f: 11~;n,4 1043:~.1 9!'i:i.•1,H t;·:)/(i,'i :1.0?::.;4,!'! ?j·1/,3 f:!)H::','i ,','N./,\t J(t(Jl(i,B 10~!~1),~! <JYOt),;~ J.:·!~j(!(;,J U~d/,,~ U..I.A7,1! U)~~~·:;:L<) ':ihlJ.,l 6?04,/ .I.O<l.l..=\,4 Bl'??.!'i lfl:.~·::;~,;{ .H/f,'/,:~ :l.()9 1lf .• ~i 9283,J lD~~·),!'i 1:'1/.~.8 U.~i92,.5 ~Ut.e.9 UnH,7 r::\Of,.S' 'i~if:~L? 9HOH,? <;':~Jfl.O j,(;;~O!J,:~ UJ'/'/,:i :1.('J1:·~Li·: 89/,L./ .I.L)()'f,~! .!.~!4'/H,:·~ U%t~.9 J.:l.:lHLJ fl:iO,LJ. ??'/'?,;~ ~i6H),,I, lt)f:.nL9 f):)1;L:-~ !l.t\,1;~),t) 6'1/9,.:~ ·j•:;:,:.:,/ 114f.:~.O 7·o:·1,~.~\ :1?443.5 u~;:·.-;9,9 ~OfHlf\,6 900f~t-~!. 7'·/:i.?,;: ·;o,LL.1. /';~.:q,::> ?::i,\6,9 '/li.J'J,!) L.l1}9,•.,3 '!":,:·,·,,';'. 94]1,9 11131.6 12542,6 11617,6 111HQ,H 9H28,6 82?1.9 6206,0 10402,5 6056,'/ 6477.6 6~65.~ 91?5.9 12312,6 7070,6 803~.4 9~5~,7 11218,1 9?2B.~ 7656.5 9~~4,1 9617,2 R122,5 12864,8 157?H,? 10011.~ 7560,7 1:1.2B0,2 12611,8 116~1.8 11.1.79,6 10J~R.l 9399,6 9454,N 99HS,1 119~2.~ 59~6,0 7942.7 9b80,4 1:1 2<7'4,1 70'55.b '799Bt0 8703,6 108:3B,8 8.9:i9,3 7:-1.~.:1.8 5~\ffi~,~:; ~~i 1i'(n.,? 5~:iBBdl 57f.i:t,? 8~'5?(),:.;: ',11i'J.H,(l 1~!~{/)4~1 l.l'I~~.O 0:1.40,1 /!'·ii!l),() 6~)~·;.-;,t, 6MliJ,~~ ~):l.'li),f:. /<l:U,/ 6 1\"lil,9 /d~!·!,.'l l):·~·.)~~~~:i /?liB·•) /'.·:'/:~.~) 12672.8 739S'.~~ W?8!),(i 7~1~1.9 t.~:·f..],f:i C.i~·8l•.7 ~;8~5-1,6 ~··;x~'4,9 7BB:id :ri'4?.o 9:?-~:i~L::;~ ~04·16,/ /Wl~;,'.' 8512,4 11llO,J 125A4,7 1166~.0 11214,5 10417.7 9414,3 10266,8 10J19,6 !1~08,5 9263,0 101~2.1 10199,0 8052.8 1092:5.~~ 124/0,4 lj:)~)9,3 LIH::!,/ 9477,8 7::.BS'.!") r)Mn,;~ nH:n .• 3 ~~4~il.() :'itl4?.!5 8'l~:.?,(l Ut .. ·H::,.f. 12279,J 704J,B HOOJ,? 7392,6 6426.~ 9067,3 75~1.9 944~,6 60.1.1.0 5796,9 ~918,7 781H,5 1662,0 26 12318.1 7119,5 8152.2 75?7t7 6~69.9 ~690,3 G853,2 8173.9 · 9~2:1.,7 H90~.6 751H,(l 9~16.0 8l9~,8 27 99/B,7 11076.8 12465,6 11356,3 lOB56,0 89&4,5 7864.0 6575,2 6444.8 5463,2 6130,6 HB82,3 aH?4.6 28 12380.2 7257,J R23~.9 7536.0 6338,8 9075.6 R112,6 ~71~,4 1023~,4 R4V9.0 A549,h 6495,5 8JJQ,R 29 11J21,0 1U97S,4 12597,1 11619,5 11197,4 10391,1 93H8~6 6723,3 55?9.~ 57~l,J 5939,2 7915,1 9117,7 30 12486.4 7228~4 S140.7 7489,2 6504.2 65B2,8 7318.3 7986,2 ?605,9 R592,4 7508.9 6047,6 78Ct9,~ 31 12392.2 9905,J 12519,0 11590.6 111~2.6 10351,8 9255,0 62Jfl,7 9431,9 9194.7 HH4H,7 837&,9 9»55~3 32 10221.4 1135~.5 12459.0 l1592.9 11121.6 10331.1 8858.2 6509.5 536h.9 84(1711 17878.2 12762.0 10~7/,9 MAX MIN I'~ "i 12672,8 11485,2 12775,0 1180318 11292,4 104~3.1 9514.8 102~6.9 10631.9 9378,0 17978,2 16495,H 6602,4 704~.8 7998~0 7392,6 6426.2 · 6582.8 5160.~ 519~.9 536A,9 5~51,0 5757.2 604/,6 ·r)M:' "]'i<},..} u···'VJ J .... ~.O ····,<J:L" f~~l)~~ "t/'}" l ::"'"}~~ '"]fl,t) ")lfl." 1~~!A'" ''J 94 ... r l ~) 5' 16 I ~) nn,o ··• 'I_._·. 'l J ,., :rl· ,, .. ·-1 TABLE 2, 36 F'OST-·PRO,tF.r;T Fl. m1s t:T GilL II CREEl\ < cfs) YEAR 1 2 3 4 5 ' " . ., i 1.0 11 12 n 14 15 :li. u 18 19 29 ~l,(l 31 32 MAX NHI MEAN Wtl h)i'lf.)/J)ftJ:(l .. CMIYON ~ r:ASE C OCT NfW [Iff: Nf.;R 7179.2 1Q9J4,4 1257Hi? 11650.3 10919.3 3865,3 £748.5 7141,1 R134,9 7~97.6 A524.0 6A31.9 ,'..BTi,:l :1.!).:\~H,J. .1.':·'6/J8,H J.P:-~6,'J .I.U.Bt),i~ 9:·l!'j9,l, 7307.4 11650.3 1266H.O 11689.A 11211.6 998~.0 7251,1 7247,/ 11896.3 1131~.6 10979.8 0919.3 7286.5 7392,? 12739.4 J178?.4 1131J,O l05~6,0 7932.9 1112J.a 12572.1 11625.2 10949,a Y079.J 8787,9 11673.8 12683.1 117?1.9 11278,3 1045R.6 J. 1) 9 :n • o :1. .1. a ·'I u ,. o .1. .~ 1. ~l4 , t 1. '· ? n , :·s .1. 1 ~~ o 1 , 9 .t. 1) ~1 :L! , ,', 7116.3 7230,1 8181.8 9993,1 11?R6,H 9119.3 'i~i~1'L9 LI.~L'i',O :1.~·~74?,7 1Hl04,':i :I.:L~Bt),:t lo4;:s9,:) 7203,6 l071/,J 12BRA,7 12015,8 1145?,8 ~060~.2 /o?;LB 1t)()t;·;~>l :I.?MltLS' U/()J.,.:) :t.1~~~s4,·;! :l.t!rn~~.l 9704.9 11332.8 12580.8 11696,5 11~81.5 10356.3 9.:1:{(),9 l.H?,LB .l.?~'j•j)~~./ .I.U)?;H,'J J.LJ<,•J.,;:I ilD:·;~~.;·i no5.s '?J9<'iH', 12 118/.~~ :ttt-<1:1 •. ~ :r.<i8JS'.8 903S',,;:, 1018~.9 11J?1,H l260H,7 11738.9 1129J,4 99~7.7 6931.1 721~.7 8171.5 9697.8 11379.8 9339.3 7881.9 11~23.0 1?7J7,1 11751.6 11300.9 10~!0.0 7Sl5,j 7724.7 8~00.2 7697,1 665~.9 h7A9,9 HR28,9 .1.1~04,7 1~762,1 11967,9 11406,1 10580,9 6453.2 ll030.l 12541.9 11619.5 11214.1 9~~9.3 A820,4 JAQ3,9 BO~Q.~ 74?3.9 6~~7,3 0j01,8 6849.9 7200.1 8268.7 7634,9 6691.7 6818.4 H527.6 1!?16.8 12~32,2 ll~40,0 10929.8 90~9.3 7001.4 7515,6 R~9t>4 7707,6 6687,1 92j4.6 ?3~6.7 11299,J 1280S,Q 11810,6 11340,4 10515,5 7190.6 7~39,1 9?72.3 7502.1 6586.6 6618.1 7096.2 9129.8 12649.5 11~89,6 11~13.6 10i~0.8 8334.0 11632.7 12677.1 11759.~ 11268.? 104~8.4 10983,0 1J.H48.8 1J1J4~1 12045.8 114~2~H 10604,2 6453.2 7j03,9 8040.5 74?3.9 6457,J ~618.1 77A4.9 96J0,8 11270,9 10~96.7 10!90.9 9285,6 l 1 ) .. I IlL SF P 7472.8 7J24,J 7.1.73,9 720A,1 12000.0 9300,0 71JH,6 8784,5 ~5~5.1 6708,4 12000.0 9300,0 7522.9 6195.0 9795.1 7901.5 12000,0 9}00.0 n:~ :1 ; , n 1 Ll ~)~:•, .:~ :1. :.~()(. S'. ;· o Tn, 1 1 ~~Mo, o s-:;,oo, <1 7H37.R 11970,4 908~.~ 71~6.1 12000,0 9300,0 790?.8 7151.~ 101A1,0 R89~,3 12000,0 1041~.4 ? ~-1 ~) 2 ) H :l .1. ~·) ~~ .1. > !·:; l :.~ ·:.~ {~ ::~ ~ ·~~ Bl·::;~:LH 8:·:i!'.i<);() j~AJ!),J 94~~.4 9008.2 9227.~ 11088.6 136!2.9 18330.0 71~).1 J2000,0 1017?.8 f.,'lfL~, 1. Li:•.)t)(), il ':I JOt), t) 7852.R 107~?,6 R4?2.7 79~9,4 127DJ,J 14~03.0 0 H :··.i 6 , 'l .1. 0 TVi >) . f) ;r;.• il , ~·,; i' ·,:~IlL 7 l ',~ t) 0 t) , 0 9 :1 i) () ,. (\ s·n;<?.-4 Ht'i'(i(),:-? 1~:;1;:'.~·;,;_) r::u:~~s.7 J.?\1(10,0 n<HL0 '11.?::;,() n:' .. ~.:··; :t:n?~L(> ~)o:~L9 :r.nn:t.~) t~iH?n.o 8 J 3 ~~ • '7 :1 (\ S' 1.:i. l 1 u J:l. 4 ( :1. 1 DB 9 I 6 1:? 0 () 0 ' () 1t !':i !'i (), 9 n ~I?, ~l 6i)O<i, ._) .1. :L·;i):··;, ~~ '/:~{)6, ~~ 1. ~!!)•)!), o ·r~:t)!), i) 79A2,B 776A,O 9213,7 9184,7 12000.0 10644,5 (J:l'?; , (~ ? J. u , o ~ ~~ B? 'I , ;·; n 8 o • ~'i ;_ ~! t)() o , o -:,; ~~ ()(J , 1,) Th'l.B :lO(il,B.,;~ 1U!;.I\,:I 9B41,3 l!H9:t.B U:.B/(1,(1 ~: !',, .1. B , ,t, .1. i) t.. S? , I. :l ~-! 0? ,£, , i) .1. t) ,1 / ,~ , ~l 1 :-! !) 0 1) , 0. !J ~~!) 0 ,. 0 :j 'J!)O' ': · {:. :·;.~,l I ii' 9 :·:; ~j 8 , B t ~~ :1 no.> , t) ? b ~~~ 9 t s ,,, o? c~ f s· ;:··i?4, B J <}f) ,1, .1., ~·; 57'89.~ S'AH'l,4 'lS1 'l!L8. ~'Blf<J,S' 'Jil9 ;.~, ~) M'Btl, 4 ""J"'J ,.!l"; 1'.' Q-l! ')I)" l) 1 1l1.1 d ~· o.l tJdt: ~~ l .·~ ~}:1~.)~7 ~ f:i b9~~.1. .. ? 899 "1 , '1 IH :Hr, ? J. ·,~fl .1. 9, H o:ue, '? ? .! ':~ J ' .1. 1H;?;,>,,1 B«) .!. :l '~~ :i. ~ ~:i ~;· ~·~ ~· (~ /) ;~ J.~! ,, ? ff:1 ~ ;1' :! ~. /j(l/;, 9 6/:HI, 4 :l. ;,•~)(!(), (I <) tlfl: .. ~ ,.l) ~. ~!!)!)!) > 0 /;41!-'1,0 ~.::l(l(iO,O Mi06, 9 1 ',~c) c)(!, i) Hl4 :rl, 6 12000. o 6 4!H. 0 '· ~~i)l)Q ,. i) 1. (l(i~;;:, n n•.)O, o 9 3()(). () 9 ~~C){) > () s·:wo. o 9 :~ () i) ' !) Y62R,5 12000,() 9300,0 6662.3 12000.0 9300.0 10003.2 12000.0 9300,0 11846.2 12~00>0 9300.0 f!9/;(l,9 :HH,t"? 1.:H?L 1 S1 ri9,4 J.:~;Wc),i) J.:s:~lO~l.~! UH~I.~.~~ i'!\146.::~ 1.8:~~1t.),r.) :·ilf!:i(i I· -1 6(l(i(i, 0 (-.(,()0, 0 f,.ivH4, 0 P<H><Ic 0 ~\H)(), 0 a :1. !) !) , 1) WI<) .s , ~S nl H ~~ , ') B ~~til, .:~ l u, :1 ;¥, ~··i :i. •.') ~·i :t.O ) ::\ Jl?fJ' 4 9·(10? t ~~) :t (1 :j :r? -: ;r! I. I\ :1 '.~ / ,. ] j H:.SO : ~ ' !.\ J. J :·:• l. 3 1:i(l().~· .1. '.i ~. ')!'}. 1 e ~56t:~ ~ :? ~.:~;J 0[-,,.? ;~gy~:.~~ 9 iJ')"d-. p 1, ,• ~:. ,t ~ 1 j · ~ ~.t)J~~3! ') ~ l r~ ~l~~ ( 7 :I.J.:}/;~.:1 T/76.··1 1i.:1 ~3(-4 t·10N'fH P (}B r ".::·:·~f) . .JEC T PF: E -·F'RO •. IF.'CT ~J A T A N ('I ?11. Cl N E t.lf.ITf.tN(I/JJEV :r: 1.. Cf.tNYfJN Mt~X fHN NEM·~ MAX MIN MEAN MAX MIN MEAN OCT 751.;'.6 I) C• .L J. ·=-· .·~.\I'_.'·' t ,.l ~;j~;~,r-1 ''J t '~ ~:t.OMi~\1 I~• () ;·~ ,, <· ·~ 7:16'7! 6 :l ::i f, 'J : .. i I n 6(.0? .It t ()!'it.:";. 9 N 0 ',.' :~ s> !·:t ~-:i ,i) .1. :I.A!.'i ,. "J ~!:~90 > 8 :1. :t. 1 ;:s :·) • j, 6t.Jn :r. :· ,~) B99··;) .r:} :1. ~. •i (·~ :·) ') ,. ,,·. '704~~ • H 941)4.3 DEC ~'904. 9 B~. o· ... o .:1.6.-£,.4.~·; ~-:w :~ 1 •· ;~. '7A2E:.7 1 () ~-; :'; (l • (;. :l ;~~I I' !5 ~ (~ '1998. () l:l.~.:~o.9 • .h~N :~~ ~~ J. :~~ ,() n·;6 i') ' I ,,~ib~;~. t :1. :1. :1. 1) ~! t·.· , ,} 'l.l.4B , 1.) v:'-;v~·.i,? .1. :1. fiO\".i, H ?39~-! .l) :1. ()4fl4 . () F Ef.: :l!?.:?;/.;.4 700.7 :1.1 !=j;t, v ~:i ~.ol:':i:?.9 ()~~t:~. ~ ~~j f; B ~·:~;4 , !\ :1. :i. ~~~ (/ ; .. ) " l~ f.~.26.? '· 009~L B l"iAF: 1 '1' J('j . ·' ,/ '·' ,/ 6l-, '~ ,. B 1 i) 4 ~~ ' l 9 ~!? () ~ 4 ,l·, :·) ·~ :1. ,i} B ~·~ c} ~-~ ,. .1. :1. () 4 ~).;'1 ' .1. 6:5H~!. n ~~:;!()2. ~') 1') r:·r;: ?40~:;.4 /·. <j' f:, p ~.i :~;;~f../.0 1;' :l (l '7' ! () ~:;?63.9 '?f..rt::;' '+ ~) :~ :1 ··l , H ~:i :1. <'· () ,. 6 'l''t ,L., ~-,, f· ;A;, M f~l y :1. S'//6, B ,·~ .-:\ :.~ '? l-~· 1 ~) :1. 9{) > ;~ l .;-, () ~: ~-.. ~ , l r·i B o :t. ') ) ·". l,) ... , &·: ••.• .I.) J d '··"·J ) .. · .. .1. 0:~!66, a :'il91 ,'-) lb62i'~ ... ~ ..JUN ,1 J n l6 • ·1 :1.1?09.8 ?60'/8. 1 :2:n:-!R.o :';:';98. 0 <J' c<, H :;' , I :t (l f., B :i. ' ~' ::.:~l,{;. 9 flj 7li I 0 JUL :~?.5Hn ,. .-:\ .1. ?:-:<.J :1. > () ~·~ ~i :1. !:; ~~ ~ ~:~ :1. ~~ J. ~) .. ~ . '/ ~-; BO ~:; ,H ?B9J. .. , 9::S7H .o :-)4!')1 ,() /078.2 :• I AUG :·:: ::·; :.?.7 () • (i :1. ~:1 ? ~-.i 7 t 0 ~~~07'~')8 ~ ~~ ~~:~:~;>~:~6 y 0 99/'1 . {. t?Ol!·) 1!' ( ,,1 :l.'lBJ(-l, ;~~ ~-) "/-!~; i' '";t. 8~~---1?~2 ~;;EP 1 ()"}()() •• ; I .• ,'1 , .1. ·11 .:) b :·~ ) .-~ :1. ~: 1.\ :L~ ,6 1. ~-~ :s 9 () , :~ .~, I .• , • ') / \) .~ ,,, ,o WI :~ ~-! , ;:s :1. f:· /j 'l ~:; • H 6047,l> 9.1\(;0.() {4 N N U f'1l.. ~.0946,:~; 6BOO. :1 $•j?9.7 :l.(l?6:L7 7 ;:.: .lj l. '') + .,;. ~·' ~-:~ l ,H :1. 0'-J'i~b' !) 7 :,ll.;':i' 0 91.2t.8 1> I - -J I TABLE 2.38 f'OST,·F'ROJF.:CT H.OI~ (!'J' f:UlWHH~F. (cfs) \•h1 T MlrVHF 1H 1.. CtHIYOH !. C:·1HE C YtM: 1 ] 4 5 6 7 8 '1 10 11. 12 n H 22 28 30 OCl ItEC FFH .Ill!. SEF' 11847,2 13990.4 14750,2 lJJ71.3 12427.3 10172,3 H9J3,H 1!1)12.3 3~191.9 41785,1 16969.0 2H7~J.O 15l~b.5 1055~.1 108JR,9 9467.6. 8139,0 H0~5.9 908~.6 ~6890,5 1~6~7.1 5~6J2,~ SC,6B6.0 3~129.0 H9HLI. :LDH?..t. l4:··;~i•.),(·l J::E5?,L,,'J J.'?b':JJ...fl .l..UM.,,~, H?~i9,:·l .l.'?l):t,t.].i.) 46:t.t.:.L? ·1.(;1\<1:~>!) ·14·:1-:\],.t) ?M!'/7,t) 1t.499,:J 1~i:5~i2 .. ~3 1S04B,O .13407,t. j~.lTH,b jt4f.:O,~) :lOH9 1LP. ·'l~~?fl)',:r, ·1f:.B:·."·~.6 .~(11.;(,'?,1 4134.<!.() ~27"//.7,(! 14H?·L7 to~:J'J,J JtU7~L~i J.J6\l:~,t,. J.~!(·i(lfLH J.0:')6:L3 'i'B0/),(.1 ·n.t.W·.i,.:) ::;B,'d•),:l 10.1.rn,•1 nb•.lLO :;:11/;;;.f,,.t} 14104.5 10972,2 1~007.4 j~91~.4 13100.0 12013.0 92~0.8 19590,2 4Q~8/,0 522~8.~ ~394?,0 31~39,~ 139?2.9 1X590.B 144JJ,l 13?~7.1 12265,8 10148.3 liH46.B 27073.~ 5~3!13 2 60~67.5 ~ll12J,9 ~4493,0 182:LL9 :ISM::;-,8 1~i44S,j ~Jj(l?i',S' :I.T:~1l9,J. 1:'1.\l?,f .. 10!S.t~O.B ?H9'VH0 t .. f.l4(!l::;,.J L\;~:t:?-'1,1 'll(J(I?t~CI :H>'!:n,H 21170.0 J.6926.H 16i)09.1 1~R99.J 12996,9 11877,6 11331.~ ?3067,2 4~2/9.? 1~952,1 ~6362.0 ~18~8.0 13883.3 10411,1 10?60,8 ll932,1 13038,8 104j9,3 94??.8 )41~1 6 49~HR.7 50470.4 53551,3 34~911,0 1H.t.l.:.~.9 J.:·iJ·l/,t) :l.:··i:i/2,7 ~.:ii)J.B,9 :1.:·)1)~~9 • .1. :1.:1.9.1./,:) :l04:·!4,:.J ?9.:.!:.~?,9 J•.>T:•?,~i :):'~:;1)1{,7 1.\:·s'?~::!i,Q ;~1.H/.~.•) 16405.6 13856,3 j569A.7 1433?.8 13l76.8 12~7~." ~7218,4 ?597~.2 ~1(171,2 ~7906,) 50516,0 32001,0 l~JJ6,B 14019,9 15400,9 1402~.~ 13076,? 12007,/ 11076,0 1Y?:J3,5 57265.0 ~0937,9 55162.G 39711,0 16937,9 14~84,8 15270,8 14170,5 13~0],5 117~5.3 95?/,7 27l?A,1 ~21~3.1 55?0~.6 41?6H,O ?8~12,9 2J!):~f:..9 :1.:').1.,')(!,8 :t.:\,'>~1?,·/ ~.;;~~H7,9 l~·~b?~).~~ :1.1):1.'.);.~,,~ il9f!;},.fl :l.O.'L'~B,O l,i/9;!,~:~ ~l~:i?:·,;~.:.'2 1:1.9:~}~f,!J :>·.~'/'),<,,i} l/.4~r?,8 LH{f..(;;:,c. 15812.2 14014.1 1?94t.8 l\1!7'~)'7.:3 H;o::.?.H t·~;rn.<~ 4?o:t.t.'i ,11.dHi1..,/ 4'.i'?~i~·i,\1 ,1499·:~.~-:; 21189,9 14~4~.8 15021,7 13742.9 13002,4 11~~2.7 l0~00,R 13951.0 49~1R,5 42763.~~ 5217/,0 27!06,u 14319.1 9907.7 10~27.5 l1895,B 1J273.8 10932.3 92~1.8 27500,6 430(16,1 60J6A,3 ~5318,8 J7J7Y,O D68/,9 J.44H3,t) :l!')~1 ~!:·),.f. Dn';:t.,6 U~~B6,9 1.?~'·i!HLO U.%:7,'> 3.1.<\:n,J. ~·j;·;.~')!b,i) !)T/8/.,,fl .1:1,~) •. '>(),() ;~069,(1 :1.3141.6 !7'75;),/, 7'989,0 :f();Hl(),.f, 11710.£) lO:U..:t .• J %4•1<.8 Hl:l.'l<•.~'.• :·~!)9'\9,/ ;·i(:.~:)6,0 ~~0(;48,0 ;(B!;,~"(' u 2 :L 1 , J. ?i! 1 :L .~ J 1) :1. 7 n • .1. ~n ~u , J. n ;1 '1 ;:;:, •J H :) 'Is) , =\ [·:~ ~ -1 7 , H ~~ .1. t) s ;L n .:•: ~~ s> T;~ , o ~ ;; ., :n . ~ 116 9 <).,l, , o :? .n? o , o l4491.1 1178~,/ :t.lH\1,2 S'!'i80,1 8j2:3,~· f~Li'~l,'? nw8,il LHM;,1i' ~~H'/:1.,~·~ 'l/~;B/',4 !iltii(lY,O ?tl(l:il.!,~·:; ~ny·),l.) :I.!')J;·;,t),? :l~·iJ.?4,J. 1.:Hl8!),'J :t:·)~./9,,1, ~.~!09?,9 :l.~.tY);i,g ~~(,/.,'/!),•) <i!i:.~:}!:i,~l ·'\0984,() <\:·)'N)~,O :~J.o:·:i_<., .. } .152i5,2 H79!'L1 :l:il0f .. 9 13731..~; :l;~S'S'Bd U17:),;~ ~'4?;~,f) :L~\!(l(i,'J' 'tO•~U ,7 ;~~'S'·1!'!.(l •1?71>~;,() :?!'·!1;(,4,0 14371,4 10279.9 10530.5 9431,9 ff199,J 9597.8 9518.0 2~9.1.7.5 J~964.1 3927~.9 3901)7.0 26l6t.0 1541?.9 j(>4:~fL1 :L04·~~).7 9Mt~,9 H~!~.t .• l s?;,::n •. ~ 7::.::.6.5 n~ip,;; s;,~~Pl8,.~ :'iB4<i9,6 4!:i!~·llBJ; :~ss:·,'.f',o l63!'i:.Ll; .1.3<\6.1..8 :1.418::i,?. ,.:.'9/:l,O U.DI),.S .l.lH·:.)i),~t, 9B96>f1 J.HJ.'i·•LSi .W'J97,'? ··l~w:·.;(),l) ~n~;:';,.() 209:?1 ,t) 13747.4 10753,6 1137~t4 J0109.6 8109,1 10RR5,A 101~~.8 2?79~.~ 6~~95,0 4119~2.5 47917,0 ?9379.0 ). 7 HJ .. L 7 14 9<)•1 , ;1 :1. !):LS~!, ~~ n 99 LiS ;t,',.~HY9, 1 :t. H· 1. :) , ~') 1. D:B, :·) J. i'i '\ ;1, <l :~~·:;·;~!.' ,t, , } ·~L'\ ~j '1 ;.! , :) ;p /::~~L 0 :~ ,~l'fJ ::; , •) D506,t. l0552.1 10SS'9,;:.t. 98~i9d 8!)0f ... 6 e:381.1 96:117',!:; :?H!:i?H,? 1\~~·H;;~.~) :;:,~B~'7d !}(;~~~J,?,O :?.~·1;1,?(1,.(, :::-~·I.) / .. ·:, t· t l .t) () 6 H I /. ·..-: ,~ ~-:~ ~\ f: ~-~~: 2l .c1 '? ? .;-() ? l >~, t'., f_. -< •;I ~ .. !:i. Y?·f' ( 9 - HAX 21536.9 16916,8 1A009,1 1433~.8 1J402,5 12~08,0 12218.~ 422fl7,3 73798,2 A0567.5 65318,8 44997,5 27588.4 NJ.N 13141,6 9ni~,6 99R9r0 s·;;B3tl Bl:n.9 803~L9 7~',~(!8,./J H::.:w.o :·~(<~:',/,5 3.t.$•:Jt,.() ?i7i':?£L(i ;,~M?:l.(l J•i'Or.f:,t. MEAN l~)8,SH,7 :t·;!9(~iL4 1]6()~L6 i?!j,~Y,/ HH.UL!) .l.tl/n,:··; n;>o,::! /<~'.1/,!'i :.)/):~:~~,!,:1 .:}/.<,:.z·:.~ •. S 47.t.~·!'L4 :·~':.1 •;!!),7 ?.U.l~LO $ TABLE 2.39 POST-PROJECT fl.DW AT SUHlTNA (cffi) ~ltJTM·!MJ)E!JH. Ci'lifi!JN t C:~SE G OCT NOV .JAN FFB . JUN ,I IlL 1 277J.J,6 19718.5 17336.2 16693,2 15406,8 13516,0 12259,7 62!0/,8 119194.6109495.9 995S1,8 40330,? ~~~0,.9 2 209?6,6 1277~.9 1J01~.A l3611.2 1?998,9 1?273,4 12815,8 53967,0 680l9,7107J02,5 Y3276,9 &l~~1.0 40~~3.f 3 :~;~3·;~~) .. ? 24o:ii.),Y .tn:·p,.~~ J.Bt~t)1,? ln.t.:?,o ~ .. :i~·;:·;~~ • .'J :t?~W?,9 t.i61)/Q,~IJ.£)'~·;·n.~:;J.,.Bfn:.t.,:~t(i~'~~M.1 '//.;!(""'':-:. !J'!::n:.e ·4 440~.i/'.8 2.1\4·~;:,1 ,•1 20:?14.0 186!ifl.3 :1.?16(·,,1 ~:··.il):i.:::,8 Jti:\iJ~i,.l\ H<tf:?::.,~l:l.:l.~i:'.:IO,IJ:I.l:;~:);,t:-:;,;~ B~'f•<r0,0 3Hi'l'?,7 :1'.<',;"•/., i 7 " 1.' l1. 12 u l4 1 !) 16 17 18 J.'? 21816.2 16976,9 1566/,9 17217.6 14972,9 1J119.0 25812.2 13800.0 16877.4 j7?43.0 157~~.1 14/51.6 22905.3 19745.7 111~66.8 16824.4 16010,6 14~h3.7 44803.5 30171.3 24687.~ ?0~~2.0 18131.4 16611.7 '1:';.:10?.0 ~!:tlill.:.\ 2l)!iO!'i.<l J.nO~i.? U,~!H'?.H .l.~·.i9LLA 32848.4 14608,5 11432.2 1~340.? 16544.1 13804.8 ~H/36.0 13891.5 17554.3 1~676,2 16133,:1. 1489~.7 331~1.9 20661.5 2~960.9 ?2262.9 l973~.8 l798~.8 :;,o UM , !\ ;~ o ~i i),1u:! l ~·~) ;p , !'5 H!H:·i L :·; n:i9 .1. 6 , 'i' '1. •l? fLL ~1 30698,1 19281,3 2944~.4 1H767.2 17~3S.1 15~14.4 40928.2 20925.4 16!30.7 16942.0 15106.9 1~01~.7 29761.7 16854.6 1740?.8 1759~.0 16175,6 11309,2 39535,1 215Jb.3 202.1.7,0 .1H369,7 174B2.S 1~730.1 29164.3 18575.3 14993.4 16226.3 1770~.9 14822.5 t)t)'Jt).l,,~ ·;!<)Y•l?,P, ~!~i/6;~ •. l ~!JT?·'L8 ~~<)'n:L:I. :t:t;~n;,~,() ,.301ti.2 J J ;t (l :·; ' l) 1!':;:1, :~ S' •. 1 J.l,>)~l.l. ,!) ~~996,2l193i3.Bl~02l~.H10~370,0 496~8.6 ? t. •l i) / , ·:i 1. .:w? ~l c , J .1. 4B a 1 :~ , :t. .t. ) \) 7 l) '7 • ,1 :t ') 'l? .1. n . :l ~ROl0.~1~74J~.112)l10.~lt6?72,9 7Hl97.8 :l ?.()? () + b ~:T :i. ~~ :·:,? , 0 ~)) :~ '? 0 ~:, , <' 1 ~-~ 9 :i. t. b { ~.> ~ .t. 9 r,-3-; 'l· 6 f.~:~~~; B /. 1 ~:.i l ;·);w:·),;:; tl <l!'i J?, !·, ?~-; J. BO, 9 J l :~6flH ,. ~-:1 !)nl\ :1. , 6 7'J ;-, :\:\, ~~ j6912,0 /H7Y6,Y131900.31?~?J~,?10659~.5 511431,3 1~1JO.~ 49~lJ,3lJ2777.012662J.~115202,0 74806,~ i.:)M'?r-4 4:f/f)4,:J l'l:V,),O:t;.•:V:M.7 (,-~·i<,:t.6,B 7\,\J:I./.,:-; ). ~~ :1. -;~ ,~ > ,t., ~~ :' ~! ? 1 ~ ? .i. J. ~··.i ~ :~ ~-; ). > 6 J. t 1. ;~ ~~ ::~ ) 0 (i /-H :~ (I { ~ ·J ~ ~··; .8 ,·) ~·~ l u 1372?.9 ~4?61,~ 9~S9H,5lJ~75i,?i027~~,9 R12J8,B :1. ~1 (-, :··; J. , :l .:) 9 / i; ~! , 4 .1. () ~-; .t ;·) :~ , J J.l) :··; .1. ) } • 9 I. 0 H B '/ Y • :~ 6 :l <1 :~7 , ~ DBB'.h 4 :'iNS~·; I;: U.ll j';J:) I (lj t ~·\V: 7 I f., :i. H'HH9 < 8 Bi/~)7. {) 1. ,!, J/:t, :-~ :w~; J. :j, :~ .1 •. 1. u::19:~., ~~ J.l 'i ~;,t.:·) , . .; H J.'N4, :) 'l:~n.t.i?., n !} !') .t. {~? t l ~(J ~~·· jr., .l' :~ -~-; ~~~ :l 6 0 i (~ ~-~; ·.f. ~j :.J ~; + ;l 2(1 2:3940,1. 163~i9,() 1395:--;.5 1~61:3,6 lf:.:l.-43d L"{,)/·1 .. ~. 1271LE; ·~\·?E~fl,:) 94~'(l(,.'J1(i:X.?}.!l,9 rt?7!).1l.(l 57?9!:,.,t, -1:'.1.:1./,:·: 21 :.ntJOO.~'j :l~~/%,6 1.~~.1~1,',,:') J.~~fl~)/,~1 l:l.<l·~~?.~-! .I.,Y:/9,<) J.J·~~66,? :\B·:iO~:,? ~l:}9:l:!,l..tJ.B1..~i',l~.~)<J"J·:~~,(l thl/,~ .. 3,~! '·.::1J,~? 2-1 ., ,, .... J 35044.4 2()~1 24.9 l-'11313.4 1~~/.~.;~,F: t:I.B/';:),7 i1?(:•?f5 10,t,~:;:),'.r' :~?t-.. :?6.:~ '7'B0:-':1,,l:i.~~:!.9i~:\,S11.:~100.j Mf.:~.'),() /;:::'~·:.:.~ .• :. 3~)74:·i,:l ~~:n.t..~.6 J.:N>•l:t.,9 :t90Ml,f, l.i'H:\6,4 l~·.i-10.'\,'/ j_.:lf<U,/ ,;;-:~:;~;:.~.~)J.:·)<\:IJ.3,/J .. :,t91'7B.fll<h):N6,6 ~'/L!t>,~l ~iiJ.;:,?,:l 28409.1 23630,0 19??4,0 lB02k,7 17490,8 14841,9 14291,0 6231Y,91(iJ?l5,811159h,2 9D970,B 4~4~2.8 1~696,8 '2. ··10 fl.~, t :1. ~·it>'i·L ~~ :l :10ii/, :·) L'~ 'l~'i:l. , ~) 1 ~! ,1·;u , 6 D67 L ~) n:·)b:L 6 :)~WB?, ;~ :·~?I)H~i , :1. i)() 1. '11 , ::~ :1M ~H , !1 ::; ;-q? .L !i :{.;. :' :L:. .. ,: . 26 2~630,9 1~900,1 16084,7 14715,9 :1.3030,7 12466.~ j1~63,5 4i677,410R~l?,61JR4l7,6 B~?JO,l 707~(,,1 ~~J9~,j :-! 7 :1:~ :~~~;1 , f, J. 9 .t, ~)(l, H .l.l4~i J. , ~! .1. 6 9'1~5, 0 1 :)!')'):'), H t :S~)\) 7 ,. :5 1 ::w:·:;;~, H 6~') ?.~!) , () ?•.)6;·'; .1. , '/ .l •.)::!:J.Ii 4,} '1.1. :1:··;~), ,_ :; ~. J ~; 9 , '\ ·I !1 '.)tl i;, •':. 28 3326?. 4 n o~s, 6 H ~ 8!1. 4 15978,6 DS·fw, 1 H.-WIL 6 :1. ~?rn:··;. ~~ :) jJ;O:L :) 'lAo~:-::::<~, 3 :t :wt..:w, 5 j j H::-:6o, 1 fW-1 /O ., ~. 51\1 tJ. ,. t 2 9 ::Z.Bi/ 1. :·; l 7 ~!<H<J-:l '3 ). ?I .1\:·l > '? 16 ?~';;.;, 6 U! -'l "l ~~I ~ J. :·;~:ii.)l) '~:i ~ ;)IL~ 4} !') 4]? l) (;. j <~ JH~)·)'~~' / J. l):')•,t4 ~!I ~ '17"/ .1. 0 > :.:~ :) (, 19 :~ '!) :U ·:. 4 9' l) 30 39093.6 J990~.1 J5097.3 15008.1 13246.6 12430,j 14~98.5 7591?.310345~.512~623.11197~0.0 /2870,0 ~246},1 MAX 33~07,0 3017l,J 2576J,l 22?62.9 209JJ,l :1.7986,8 l6912,0 SH6l5.~1~7~74,1141l013.1120709.4101218,~ 59701.9 MIN 20926,6 12773.9 11432~? 12763,8 11427,2 11699,0 10655.9 ~26?~.2 57089.1 90191.~ 76031,5 ~RI97.7. ~b~'H6.~ MEAN 3?514,9 19912.3 .1.//01.8 170?4,7 1~~~9.8 :t4426.2 1J644,/ 562SH,1106171.2ll~i't],J1026~t.9 6~887,6 1~1)0,1 l ·-J I . _j 0~ coOl< INLET 0&~ e ___) r "1 HEALY e06n PALMER (&) 0688 DATA COLLECTION STATIONS STATION lA) SUSITNA RIV'£R (8) SUSITNA RIVER (C) SUSITNA AM:R 10) SUS IT NA RIVER (() SUSITNA RIVER PAXSON 0 0676 06&2 NEAR 0£NAU AT VEE CANYON NEAR WA.TA.NA OAMSJTE NEAR 0£VIL CANYON AT GOLD CREEK (F) CHULITNA RIVER NEAR TALKEETNA IG) TA L KEETNA RIVER NEAR TALKEETNA IIi) SUSilNA RfV[R N(AR SUNSHINE f I) SI'(W[NTN.l RrvER NE.AR SKWENTNA IJl YENTNA RVER NEAR SJJSJTNA SThTION HU SUSITI-U. RIVER AT SUSITNJ.. ST.\TION (L) MCLAREN RIVER AT PA XS ON X X X X X X X X X x2 X X X X X X X X X X X X X X X X X X X X X X 0 Q:: 0~ oo i:'c.' ... ~ o: o:: !?., Q:: "'"-"-0 X X X X 1957-PRESENT X [1961 -!972 a 19 60-PRESE.'fT X X X X 1980-PRESENT X X X X 19~ ~-PRESENT X X f 195f---1972 II l i9BG -PRESENT X X 19 6~-PRESENT X X 198---PRESE>;T X X 19~9-1980 X 198{; -PRESENT X t9H -PRESE NT DATA COLLECTED • STR(AI.<FLOW-CONTINUOUS RE CO RD 0 STR£AI.<FLDW-P>O.RTIAL RECORD It W.O.TER OU4UTY T WATER TEMP£AATURE "' SEDII.<ENT DISCHARGE 0 CLIMATE FREEZING RAIN AND INa._OVD ICING SNOW COURSE SNOW CREEP II-IOCX Ni.JI.t BCR i h'G 0+00 0200 0!>00 0400 O!lOQ 0600 0700 oaoo 0900 2.-CONTINUOUS WATER OUAUTY MONITOR INSTALLED 3. DATA COLLECTION 1981 SEASON "-TliE LETTER BEFORE EACH STATION NAME I N TliE TABLE IS USED ON THE MAP TO I.<ARK n-tE APPROXIMATE LOCATION OF TliE STATIONS _ 5. STATION NUMBERS UNDERLINED INDICATES DATA COLLECTED BY STUDY TEAM IN 1980-82. ~ COURSES MEASURED -ARE NOT UNDERLINED FOR CLARITY_ 0 10 20 MILES SCALE (APPROX_) FIGURE E.2.1 Susitno R. near Denali THREE PARAMETER LOG-NORMAL DlSTRIRUTION-WITH q5 PrT (I PARAMETERS ESTIMATED AY MAXIMUM I IKLIHOOO 10E5--------------------------------------~~-----------------------------------------------------------------~------------------I I I I I I I I I I I q ----------------------------------------------------------------------------------------------------------------------------' I B ---------------------------------------------------------------------------------------------------------------------------I I 7 -------------------------------------------------------------------------~-------------------------------------------------1 I 6 -----------------------------------------------------------------------------------------------------1 I • I I I I 5 ------------------------------------------------------------------------------------------------1 I I 4 -------------------------------------------------------------------------------------------I I I I I I 3 -------------------------------------~------------------------------------------ 2 ------------------------------------------------------------- 1 I I I II I I I X I -----------------------------------------------1 I 1 I I I I I I I I I I I I I I I I I I 11 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I I 10E4-------------------------------------------------------------------~--------------------------------------------------------1.005 t.o5 1.2o:; z.o s.o 10. 20. so. 100. 2oo. soo. RECURRENCE INTERVAL IN YEARS X--OASERVFD DATA o--FSTIMATED DATA 11--q51 CONFIDENrF LIMITS ANNUAL FLOOD FREQUENCY CURVE SUSITNA RIVER NEAR DENALI FIGURE E.2.2 1 1 1 1 l ] SuHitna R. JlCilr Cnntwell l 0 r. -r: 0 IH' A L 0 I ~ T ll J[l 'j t I 0 r I -lll T fl 'l ~ P CT C l 10[~----------------------------------------------~----------------------------------------------------------------------------~ ----------------------------------------~--~-----------------------------·------------------------------------------------- 7 -------------------------------------------------------------------------------------------- A --------------------------------------------~-------------------------------------------- 5 ----------------~-------------------~-------------------------~------------------- 4 ------------------------------------------------------------------------ ? 1 ') [ 4 I I I I I I I I I I l I I ---~--------------------------------------------------------------------------------------------------------· I ·I I I ? --------·------------------------------~--------------------------------------------~---------------------------------------I I I I I I I I 1 I • I 1 I I . I I I I I I I I 1rr3--------------------------------------------------------------------------------------------------------------•-------------.1.005 1.os 1.zs 2.0 ~.o 10. zo. so. 100. 2oo. 5oo. X--nnSERVED DATA 0--ESTIMATEO DATA •--95( CONFIDFNCE LIMitS RECU~RENCE INTERVAL IN YEARS ANNUAL FLOOD FREQUENCY CURVE SUSITNA RIVER NEAR CANTWELL -i FIGURE E.2.3 1 l -1 Susitna R. at Gold Creek THRFE 1-'ARAMFTF~ I OG-NORMAL 1)15TRIRlJTION-W!TH 95 PCT CL PARA11FTFRS f5TI~1ATfl) IW MAXIMUM I.IKLIHOOD lOFn----------------------------------------------------.------------------------------------------------------------------------ q ---------------------------------------------------------------------------------------------------------------------------- 8 ---------------------------------------------------------------------------------------------------------------------------- 7 -----------------------------·--------~------------------------------------------------------"------·-------------~-----~---& ------------~------------------------------------------------------------------------------------------------------------~--I 1 5 ----------------------------------------------------------------------------------------------------------------------------1 I 4 -------------------------------------------~-~------------~-------------------·---------------------------------------------I' I I I I . 3 ·----------------------------------------------------------------------------------------------------------------------------I I. I 1 I I I I I I 2 ---------~-------------------------------------~----------~~---------------------------------~---~------------------ 1 I I I I I I I lOFS--------------------------------------------------------------------------------------1 I I I I 9 ----~---------------------------------~------------------·~-----~-----~------R 7 5 4 I ·--------------------------------------------1 I ----------------------------------------------------------1 "----·-------------------~----------------------·---------------------I I 3 ~---------:--~~~ -------------------,------------------~~----------~--------~---------~-----~------i------j I I I I I I I I I I I I I I I I I I 2-,------------------,--------------------,-------------------,----------~--------~---------,-----,------,------, I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 10F4------------------------------------·----~----------------------------------------------·----------------------------------- !.00'5 l.O'.i lo25 2.0 5o0 10. ZOo 50. 100. 200. 500. PECURRENCE INTfRVAL IN YEAR5 X--OASFRVfO DATA O•·ESTIMATFO DATA *••95( CDNFJDENCF LIMITS ANNUAL FLOOD FREQUENCY CURVE SUSITNA RIVER AT GOLD CREEK FIGURE E.2.4 j ] 1 M&claren R. near Paxson THRFF PARAMFTFR LOG-NORMAL DISTRIRUTI1N-WITH q5 PCT CL PARM1FTfRS f5TIMATfD RY MAXI~'lJ~1 UKLIHOOD 1 ] ] IOFS----------------------------------~---·--------------------------------------------------------------------·---------------- 9 ---------------------------------------------~------------------------------------------------------------------------------8 ,------------,------------------,--------------------i-------------------,--------------------------------------~----------, 7 ---------------·---------------------------------------------------------------------------------------------------------~-6 -----------------·---------~------------------------------~----------------------------------------------------~---------I I 5 ---------------------·-----------------------·------------------------~-------------------------------------~-------· I I I I I I 4 ---------------------------------------------------------------------------------------------------------------1 I I . I . I I I I 3 ----------------------------------------------------------------------------------------------------------I I I 2 -~------------------------------------------------------· ----------·-----------------------------I I I I I I I I I 10F4-----------------------~------------~.---------------------------------•--------- I I I I I 9 ------------------------------------------------------------------------A 7 -------------------------------------------------------------- : I I _, _ _.....,. _____________________________ . _______ _ I I 5 -------------------------------------------------------------·---------··-·-----------. I · I 4 ------------------------------------------------------------~----------------------------- 1 I 1 I 3 ----------------------------------------------------------------------------------------------------------------------------1 l I I 2 ~------------------------~--------------------------------------------------------------------------------------------------1 I I I I I I I I I I I I I I I I I IOF3---------------•---------------------------------------------------------------------------------------·--------------------l•005 1.05 t.25 . 2.o s.o 10. 20. 50. tOO. 200. 500. X--OASERVFO DATA 0•-fSTIMATEO DATA *--951 CONFIDENrF. LIMITS P.F.ClJRRENCE INTERVAL IN YEARS ANNUAL FLOOD FREQUENCY CURVE MACLAREN RIVER NEAR PAXSON FIGURE E.2.5 ] l Chulitna R. near Talkeetna THREE PARAMETER LOG-NORMAL DISTRIRUTIQN-WITH 95 PCT CL PARAMETERS ESTIMATED BY MAXIMUM LIKLIHOOD lDF5---------------------------------------------------------~------------------·-------------------------------I I I I I I I I 9 ---------------------------------------------------------------------------------------------------------------------------1 I I I I I I I I I A --------------------------------------------------------------------------------------------------1 I 7 ------------------------------------------------------------------------------------------1 I I b -~---------------------------------------------------j ___________________ j ________ _ ----------------------~ I I I I I I I I 5 -----------------------~-----------------------------------------------~------------------------------.! I 1 t::::::::~~-~-----~--------------------------------------------------------------------------------------------1 I I I I I I I I I I I 3 I I I I I I I I I I ? ----------------------------------------------------------------------------------------------------------------------------1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I* I I I I I I I I I I I I I I IOF4----------------------------------------------------------------------------------------------------------------------------J.005 1.us 1.2~ 2.o 5.0 10. 2o. so. to~. 2oo. soo. RECURRENCE INTERVAL IN YEARS X--DBSFRVED DATA 0--[STIMATED DATA •--951 CDNFIDFNCF LIMITS ANNUAL FLOOD FREQUENCY CURVE CHULITNA RIVER NEAR TALKEETNA FIGURE E.2.6 Talkeetna R. near Talkeetna THREE PARAMFTER LOG-~ORMAL DISTRIBUTION-WITH 95 PeT CL PARAMETE~S ESTIMATED BY MAXIMUM LIKLIHOOD 1 ] ) l l lOFb-----~-------------------------------------------------~---------------------------------------------~--------------------- q ----------------------~--------------------------·---------------------------~-----------------------·---------------------A ---------------------------------------------------------------------------------------------------------------------------- 7 ---------------------------------------------------------------------------·---~-~------------------------------------------ 6 -----------------------------------------------------------~----------------------------------------------------------------1 5 ----------------------------------------------------------------------------------------------------------------------------I I 1 I 4 ------------------------------------------------------------------------------------------------------------------------I I 1 I 3 --------·----·~---------------------·-----------------------------------.----------~-·-----------------------------1 r I 2 ----------------------·-----------------·-----------------------------------~~------i---------~----------- 1 I I ' I I I I I I lOFS--------------------------------------------------------------------------------------------1 I I I I I q ----------------------~-----------~----------~-------------------~--------------------- 8 ------------------------------------------------------------------------------------ 7 -~------------------~----------~-------------------------------~-----------------1 I b -----------------------------~-----------------------i--------------------- s --------------------------------------------------------------------I I 1 4 ------------------------------------------------------------ 3 2 1 I X--OBSFRVFD DATA 0--ESTIHATFO DATA •--qsc CDNFIDFNCF LIMITS ANNUAL FLOOD FREQUENCY CURVE TALKEETNA RIVER NEAR TALKEETNA FIGURE E.2.7 l Skwentna R. near Skwe1.tna THREE PAI~AJ'IETFR L Oc;-NORMAL I) IS TR I PllT I MI-W JTH 9'> PCT C'"L PARAMFTERS E5TIMAT£D BY MAXIMUM llKLIHOOD l lOF5---------------------------------------------------------------------------------------------------------------------------- I l l I T I l IT I I 9 ----------------------------------------------------------------------------------------------------------------------------! I T T n -------------------------------------------------------------------------------------------------------------1 l 7 ------------------------------------------------------------------------------------------------------1 I b --------------------------------------------------------------------------------------------I I 5 -------------------------------------------------------------------------------1 4 ----------------------------------------------------------------I I l I I I I ----------------~------------------------------------------------1 I I I I l T l I I I I T l T --~-----------------------------------------------------------------------------------------------------------! I T l T l I l T T l l T l T T T I T T T l l l l T T l T I l l l I l T l l I I l I l T T I l T I T I T I l T I I T 1 IT I T 10F4----------------------------------------------------------------------------------------------------------------------------l.005 1.05 1.25 . 2 .o s.o 10. 20. 50. 100. 200. 500. X--OASFRVfO DATA o--ESTT~ATFD DATA *--951 CONFTDENCF LTMTTS RECURPENCF INTERVAL TN YEARS ANNUAL FLOOD FREQUENCY CURVE SKWENTNA RIVER NEAR SKWENTNA FIGURE E.2.8 1 w > 0:: ::> u 1.005 ... j -·---·· -1--- 1.05 1.25 2 5 10 20 RETURN PERIOD ( YRS.) DESIGN DIMENSIONLESS REGIONAL FREQUENCY CURVE ANNUAL INSTANTANEOUS FLOOD PEAKS 50 100 200 500 ... --~ ----- -------- FIGURE E.2.9 - - -180 165 150 135 120 -fe (.) 105 0 ~ 90 LLI t!l a: <t 75 :I: (.) en B 60 45 30 15 0 1.005 .2 5 10 20 50 100 1,000 10,000 RETURN PERIOD (YEARS) WATANA NATURAL FLOOD FREQUENCY CURVE FIGURE E.2.10 -; - '~ - -I r- 1 180 165 150 135 120 en La.. u 105 0 ~ 90 1.1.1 (!) 0:: <t 75 :z:: u en 0 60 45 30 15 0 1.005 .2 5 10 20 50 100 ~000 10,000 RETURN PERIOD {YEARS) DEVIL CANYON NATURAL FLOOD FREQUENCY CURVE FIGURE E.2 .II - - - r --+-+- 200 v '\1 i'\f- ' 160 I If 0 g,20 )( (/) " LL. u ..... ILl ao 1/ (!) G': I .A <t ' ' ::t: i (..') (/) ·o , .... _ 40 !- 1"-i- I TIME-DAYS SUSITNA RIVER AT GOLD CREEK 100,500,10000 yr. FLOOD VOLUMES LEGEND -----100 yr Flood Volume ft3 122.3 X 10 9 Peak Discharge ( cfs) --500yr 178.2 X J09 104,550 131,870 19~000 --·-lO,OOOy 310.0X 10 9 FLOOD HYDROGRAPHS MAY-JULY i ' I I i I ' ;__r+-+-j-' -+--H- I I i ' '\ ~ ' I ., ' ' ,1/ i ' I I ' ' ' I ., I \ i \.. I ,, I ' !..-' I ' I L I' I .v I''\. .. _,_,_ ..... :;;. "-- FIGURE E.2.12 ,- - -- -·------------ 200 1-+-HI--+---H!-++1: +-_j__j__·r--+-~-+--[-r-+-+-+--c-++j,-t---++-+-+-t-+-+-+-+-~ -H-1--~LL.-f-J~~-+ 1· ~~+J-1-. +4-++ ~-++-+-.l-l--+-1--+ -+-1' ' --.-lf--H 1--++-1-++-IH---t-t· f-1--j-+-J~i--!. ' (_I---'-I++--i--_ f-l--t-t-· t---+-+i---'--, -!,--1--1---+-f-1 + . -~++ -t-+t-- 1-++~+-1-+-+!++--jj-+-; +,-!;-++-!-++ +--+lc-i-+-~-+-1-t-+-1-+-H'--+-·+-"1-+-+ +-1--1-+-ii-++-+--t-t-+-t--t-t-i-+,--+--l---1--1 f r~-t--:----t--t--t--f--t--t-t--t-t-r-t-t--t-+---+ +--~f-H-+-1-+~-i i-=t=, +-+-r,--1 1 --1---i-+-t--+--H---. 160 § 120 X (/) LL. (.) I w .(!) a::: <[ 80 J: u (/) Ci 40 0 ! ! ·"':"~I I I -!5 L I ' I l I I I -10 -5 , ' v IJ I-" 1 PEAK· TIME-DAYS SUSITNA RIVER AT GOLD CREEK LEGEND Flood Volume ft 3 Peak Discharge ( cfs} ----100 yr 53.8 X 10 9 --500 yr 78.8 X 10 9 ---10,000 yr 140.0 X 10 9 90,140 119,430 185,000 FLOOD HYDROGRAPHS AUG -OCT ; I J ·-'!.· I T 5 10 15 FIGURE E.2.13 %OF TI ME DISCHA RG E EOU.G.Ll£0 OR EXCEEDED ..IANUAIIIY ·--+· "'+-.--+-'-'--r---'-.:::,=c.;,"----+--,.;.0-+-.--..;.....- % OF TIM[ QISCH AfUi[ EQUA LL E D OR EXC££0£0 .JUN. *-_,-+-~-, __ . _ _i___ ______ i -~-'--- . i . ·;j "'"'"'--"-i "fo OF TI ME DI SCH.Io.RG£ EO U4 LL E O OR EXCEEDED .... IIIUAAY '-----1===-=t ! . l < • I ---" ---c-+---+-- -------:------:-----:- "'+---,-,--,.,--.• ,-,"'-~--,-,--.,r-, --,-~- %OF TI ME DISCHARG E EQ UALLE D OR EXCEEDED ..JULY ":~t-·· ~----' ~- -----1---- i ! J ~+---:-- ~-=~~~:~~--~-b--l---- --I .. "'f. OF TIM£ OISCHA.t£ !OUALL£0 OA EkCEEDED "Dilc•M••" "::~~-i~;· ~~~ -~---~1 ~----~--t+~~ :e 1 i .=..._ _ ___:.~·~=-£_-_· -F--~---· ·--~~- ! I · _, % Qr TIME DI SCHARGE EOU7L L£0 OR EX CEEDED MARCH ,, g --· ---··-- ' %OF TI ME DISCH ARGE EO u .l.U .. £0 0 1' E XCE EDED AUGUeT 1 0~ ! ____ ; _____ -=----=-===~~--==----:~-~--. -----------·---·-- '-------___ !....__ _______ _ ''ill~ ~"---i :-ol .... " %OF TIME DISC HARGE EQU ALLED OR £)(C£EOEO ANNUAL ' -. 5 ' ··---------.----- \ •o '-'------------------ %OF T 1 ~£ DI SCHARGE EDU-lLLE O OR EXC££0£0 APRIL 10: !---=---------------_-...:...:.-= : :-::-:_:-_- e -------------- CR~- ,, ' ' 7 ~ .tO % 0~ l i ME DISC HARGE EOU -l ~-E O 0 ~" E i C.£[0[0 MAY i '1--------~------------ ,,'+-----~----~----",, ---, o/0 OF Tl hl [ DI SCHARGE £0U-l LL£0 OR EXCEEDED %OF T1 "'[ OISC H.ARGE EOU.l.LLEO OR [KC££0£0 •• PT·M-·R NOTES I FLOW DURATION CURVES BASE D ON ME AN CA lLY F LO WS . 2 .PERI OD OF RECOR D : WY 50-WY8 1 MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT GOLD CREEK SUSITNA RIVER NEAR CANTWELL SUSITNA RIVER NEAR DENALI FIGURE E.2.14 1 ... <W TilliE DISCNMM: (~1.£0 0111 UCU:.e 'II. Of' T..: Oltc....._ EeuAl.LEO Ofl (XC[[OfiEO ,., .. "' "' ,., M T..: ...cMMe~E l~n 011 ucu•o ••v••-• "JJI. Of Tlfllli( OISCHAf!e£ EOUALL£0 Oft [XC[£0£0 '%,Of' TIIIK DISCKotoa:K [QUALI,.[O Oft EJCCEEOI:O .IULY 'II. Of' Till£ OISCKotoa:H EQl.IAU.EO 011 ElfCEEOI:O -··-··· %OF Tlflll£ DISC HAft$£ EOUALL.£0 OR EXC££0£0 , ___ . ....• =J: ,-~~--···· ~if~:;_::._~-~~-=-r~--~~-c-~· ~~-~~~~-~---~ i -F-1-'. ~ --·-'\ --r-· -r -·-. -' -1--, ;:;_: :j . '~E==-'='=' •ail--i·::c~· -~-::=~t::-:_i~i>_-~=-:=-~-;· ·--~i:..::'-~~~:: -~: =~~---'~:"'-;·· :.!f ~ -I ..., j j· ,--i ·--+ --1 . ---+--:---+ . ----r---- o:------r.-_~:=.-:~,= .. _-+1-:~---;-------- .;------ . f --=-T •a+-.---,--.-~~-,-~--.-,Oor-~-~-- '%.OF Ti lliE OISCHAA$( EOUALL[O Oft EXCEE()(O AUeUaT '%,Of Tlllf( OISCH.t.fte[ EOU.t.ll£0 011 ElfCEEDIEO ANNUAL ~:1111-------~--~----+-;~--~ i··--l ..,-_ . -·f -~ ~-~ .. :,. -r ·--, ' -~-: ~· . . ' . C:,.c,.;~ "-'.:,C,~"o-==o==:>-"-=-=~ -7-"i""''" ~c=-:--~·-· ;:-c',~~c:;.co~~-¥~ .-;=j~ ...;o -_4:-:":--··· =i-- •a' +--,---,--~-:--,-~-~--,-,;,-~-- "'I., OF Till![ OISC HAit'[ [0\JALL£0 OR [XC[£0(0 A lOll II., . ' ' --l--'-~---·-;-----+-- -i ' J :' i. -f_- ·a::~~~~ +----.,~.---_-rt--.--_+1----+-+---------~~ I. : !,· ·--t- •a' -f--,--T-~-+' -.--~-r--i-1 --_,_,-,--;, '%,OF TilliE OISC HAIUtE [01JAU.(0 OR (JCC[(0£0 .... T.Ma•ll ~:~,-~--~.~ t------t ---j-· +· ' • ~----·_-cf----'--7-::-,-:+jc:-c_,-:-~-:-.' ,-.-,--:~-'~-;-----;---' :~ "'~~-j-: .c-+:. i---i ' .. ,--~+· --"i 2030405o 10 '\(.Of TIME DtSCMAit40£ EOVALLc£0 OR [XC££0(0 MAY ' _____ L~_·_L~___j- i -:· . . . l -r r .::..T .a :--,;~ ·---t--+· ,, ~--~---+r~-~-_:;.·._-;.,:_·.;_~_:;:·_-"': rc;.:_~. -.. -'-~"--___ i~ .:_ - -T~= ---l ' " ·:-I :c--. •a' +-.--+--r--i--,,---TI-~--,-,--~- % rH filii( OISC HAA$( EOUALLEO OFt (XCH()(O DCTDa•ll MONTHLY AND ANNUAL FLOW DURATION CURVES MACLAREN RIVER AT PAXSON FIGURE E.2.15 ;: _:c~! ~~~~~~ +-----'---'------=---"'-----'--:__· '-' -------- ·;@~"----~~~~2 i -:r:--i -- •o' I-- ' . -----;,,-----r-·--+----• --------+----,---I. :- I I :50 40 50 70 80 9 0 100 %OF Ti h!E DISCHARGE EOUMLLE D OR EXCEEDED .J AN U AR Y ' r----------,-------~----- i=----. -~=---= ' r--------------'----7------ ·:~~~~ _:=-1----::___-_-_;:..;. ----+-:-·-_--_----.,."-- ••'+-----~-:_--~----,----..,--- l O .:o 100 %OF TIM[ DI SCHARGE [QU;lLLE O 0~ EXCEEDED .J UN. i r--- _J_ +---!: ! --.::-=_:-:i- ···~~-'-': --.,: :_· : ~+--:_'-: .--:': -+,_. -.---T-!=·-;: :_·. -;..i _- o4 0 50 10 tOO %OF Tlfrol [ DIS CHARG E EOUA U .£0 OR EXC EED£0 NDV•M··· ··:EF--i:_~,---~---::-:-:::::1~---~-i'-=--::-=t~-~-~~-- •E: ' ·.i l .. ___ T--+-- ------. _:__.:_ __ _:_ ___ ----;---'--_;_- 'r------~·--_-_-~---,-t-·~--------~~;~_-_-_-_-~;_-_-__ ~ _ _____ i_ ____ --------- •o' +------,---,:.... --r--,.,.----,.,, --,--,--- %Of T!ME DISCHARGE EQUA L LE D OR EXCEEDED o; . ' 6 I __ .... RUARV -----__!_ __ -- ,---------.---'--·-- ________ ____c __ ----,-----i ---.- oo '+~-----,----~-.-------,--,--~ •o ro ro ~ ~ 0/o 0~ ll"'[ OI SCH•RGE EOU .l.LLEO OR EXCEEDED .JULY _i ___ :__ --- ··'+'-----,-+-!, __ · '...;..:: , __ · '-tT __ -.:...'--;-,'--''--+T----; __ -----;-r-__ · -r--....;..-- "' 30 %Or TIME OI SCH.lltGE EOUA LL E O OR EX CEEDED ------:_:___;_ __ ;-----;-'--:---7-'--'- ----'------:------:----,-----:---------- ••'+-----.---.• -~--.. ~-,-.-... -----,--- % Of Tl!,l( DISCHARGE EOUM LLEO OR [XCEt0£0 MARCH ---------------- 9 ~ -- 6 ----: =-=-============t===;=-···r-' -----;----~ -- ' -~ ---------- ' ·•' 1-- ? 10. : --------------- % 0~ liME DISC HARGE EDUJ.U..E D OR EXCEEDED AUGIUeT ' •oo '---------------·------. ---------------· ·--+--1 --- :.:;-: i-!· !"-. I L--: ••'+---r-·--,f--~' .... ': :_: ---::-+_: .---'--r-----+-1' ---r---l-1-'-_· ..;..--' --_-;-.-- ~ co ~ ~ %Or TIME DI SCHARGE (OUALL E D OR EXC EE 0 £0 ANNUAL -+ ••'+-----~----~-----.--,--~- •o %Or T IME OI SCI"<ARGE EO U.lLLED OR EXCEEDED AP .. IL ---------------·-- ••'+-----.------~----,---,--- N OTES % 0~ TI ME OISCtiARGE EOU.lLLED OR EXCEEDED ..PT•M •• A •00 I FLO W DURATION CU R V E S B AS ED ON MEAN DAILY FLOWS. 2 PER IOD O F RE C ORD ; W Y 75-W Y 8 1 I ~ ---~-~~-_t-l ~:--_-:-__ ,__l __j___-+:--; ---j t ~;- ~-. -----1-------+-----"t--- ' '\ . . . \ ----: -. -. --:----;----'--:----C--T_ \ -: -. ···~~~-~~ ' . ' r-f---_-·{,-----+-. ~~~.· =t= _: !" ~-T -- ~ --·----·---=-·--- ••'+-----~-.-.---~---.. ,-----.----,-- % Of TI M[ DISC HAR GE EOU.lLL ED OR EXCEEDED MAY -! --- . -i -------'---· ____ i ___ ;_ __ __:_:_;__ __ : ··!~-gl . ~:-~-~- -~ --~-+----~--=--=-- • 1----__ ___; ___ .:__ ___ _:____-------- ••'+----'--~-.;...-..,;.-~-~--.. ;.., --,,-.-~- "to OF l11,1 [ DISCHAR GE EQUALL E D OR EX C EE DED acTa••R MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT SUSITNA STATION FIGURE E . 2 .16 +- !--:-· _j .:: T ~-·-1· t· ·o~~~~ ' ·-· !---l + ~-+----+- %OF TI ME DISCHARGE EOU o!.LLE O OR EX CEEDED .JANUAIIIV , --------,----,---+----: ---.......-~· -. -[--:-~------ ~--1 -;_~·-' -·-;- _! __ . __ l---i .. -r- , 0 • +--.-~: '_:...-... ~ ._:_,'!_~:_:...=-,.:, _--... 1 _____,:_--_-i--r-_"--,...· -----.-i_-_-- 20 ~ 40 ~ ~ "1. OF Tl ~oj£ DISCHARGE EOU.:lll£0 OR E XC EEDED ..I UN. '% M TUrK OIICHA11.9E E~ED Ofll UCU"ot:O NaV•M ... 10:1=~~ -~C==F=-~--;-·;-~ i--~-~·-· ---jiir-.~~ ·~:_+1'·f· !" -~-~-~---~-~-- ·-!z:~ i " ~ ·,.... ~---'~- _,.., !-.. --=-· ! . ~ _, ... §1'-:-. ·i'--. . "" :.;.~c-""""'='4 -'-"', ::j c ·'· ~~~--,- -!- t =.··. I :_ __ ·! I .. :··1.:::::.· i ' ' ------------·----------. ' . . . •o '+---,-0--.--~.0-~-~--.·o -,io,-~.o--,-- % OF T IME DISCI-lARGE EQUALLE D OR E XC EEDED ~··AUAAV •o' ! __ . ___ . _____ • · ___ . _._. __ · _ __;...._..:... __ ~-- ~F-1-~-~-~-~ , ------:-r:--:---r----r-- : f-~----t~-~ 1 r~-~ ---i "i i· . i I . ! ! !~~- l o'+---,1 0---.,.--,.--,.--~--r--•,o---i-' --9or--r-- "1. 0~ Tl .,.£ DI SCI-lARGE EQUAL LE D OR EXC:E£0£0 ..IULV ---:----·r -! ---:---,--'----'--· --·-· ---- l o'+-----.--~--~--.-0--.... -~-~ %OF TIM[ DI SCHARGE EOJ.l.I.LLE O OR EX CEEDED MAIItCH -~~1=:=~-~ 11~'~-~~~:_~r ru;.;.~i··~·-· ~ -~ ·~·- ---·---------'--·---'----'--" -____ ...L_ ---=-=--~== ' r--·---------------------------------+----\ I 0'+---,-0--.---.0---~--,-o -,io---~- % 0" TI M( DI SCHARGE EOUA LLEO OR EXC EE DED AUCIU.T •o %OF T IME DISCHA RGE EOUALL.£0 OR El!CEE0£0 ANNUAl. ~:,I:D: :-:;~=---~~:~~~-~ il:i=-1-~,~~:-:l-1-~~ :m --r--+-+ rr--;---r· -c ----i_:__: ~--i--J ___ ,.... ~\~~~~~~:~~~~-~~--~---~i ~~~~~ 10: . r----;--r=- -· ·--+-·--r- •o +-----.--,---~----.--~--,--w oc ro ~ "to Of TI "'E DI SCHARG E EQUALLE D OR EXCEEDED AIOIIIIIL --. t--~-- '-:.,.' --'---!_ __ ! __ c.:--;"--~ ,.~: f ~i l.~~~ -+·· ~~ _"'i_ __ 10 NOT ES -I -+--+-·-··+ -+--: ! "l ~---~ t· 30 40 %OF Tilli E DI SCHARGE EOUALL£0 OR EX CEEDED .... T.M •• IIII ·-+ + I F LOW DURA T ION CURVES BASED O N MEAN DA I LY FLO WS. 2 PERIOD OF RE CORD : C HUL IT NA RIVER WY59-W Y 72 ;WY81 TALK EETN A RIVER W'I'65-WY8 1 -i -~--,..,·--+-~ ·t--- ~; i t · lo '+-~---,--,--,-~----.--~--,-- o ro ~ %Of TI '-I E DISCI-URGE EQUALLED OR EXCH.:OEO MAY 10~ f -j--·--i ' "1. OF Tl ~~j£ OISCHAJI5l E~ALLED Of' EXCEEDf:O ·ae'I'&WD MONTHLY AND FLOW DURATION ANNUAL CURVES TALKEETNA RIVER NEAR TALKEETNA FIGURE E. 2 .17 - - - en LL.. (.) -I 3: 0 ....J LL :::E r-~ ::E z ::E '~ - 10,000 9,000 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1.1 2 5 RECURRENCE INTERVAL -YEARS SUSITNA RIVER AT GOLD CREEK LOW-FLOW FREQUENCY CURVES MAY 10 20 50 FIGURE E .2 .18 - - (J) 14. u I ~ 9 14. :E :::J ~ -~ :::!: .... - 50,000 40;000 30,000 20,000 10,000 9,000 8,000 1poo 6,000 spoo 1.1 2 5 RECURRENCE INTERVAL-YEARS SUSITNA RIVER AT GOLD CREEK LOW-FLOW FREQUENCY CURVES JUNE 10 20 50 FIGURE E.2.19 - - - - - - 30,000 ZO,OOO 15,000 ----10,000 (/) Ll. u I ~ 40,000 ....I u. ~ 30,000 :a ~ ::E 20,000 10,000 9POO 8,000 7,000 6,000 1.1 2 5 RECURRENCE INTERVAL-YEARS SUSITNA RIVER AT GOLD--CREEK LOw-FLOW FREQUENCY CURVES JULY AND AUGUST 10 20 50 FIGURE E.2.20 r-, r - ,..., - ,..... r· - r ' -I (/) LL. (.) 1 ~· ..J LL. :e ::I ~ z :E 20,000 15,000 10,000 9,000 8,000 7pOO 6,000 spoo 4,000 7,000 6,000 5,000 4POO 3,000 . 2,000 1,000 SEPTEMBER OCTOBER 1.1 2 5 RECURRENCE INTERVAL-YEARS SUS ITNA RIVER AT GOLD CREEK LOW-FLOW FREQUENCY CURVES SEPTEMBER AND OCTOBER 10 20 50 FIGURE E .2.21 rn 50,000 ~ (.,) 0 40,000 LLI 0 LI.J LI.J u 30,000 X LI.J a: 0 0 LI.J ..J 20,000 ..J <r -;:) a LLI 5: 15,000 g -~ 10,000 9,000 r-, - - - - 1.1 2 5 RECURRENCE INTERVAL-YEARS NOTE: PERIOD OF RECORD IS 1950-1981. SUSITNA RIVER AT GOLD CREEK HIGH-FLOW FREQUENCY CURVES MAY 10 20 50 FIGURE E .2 .22 r- en "-0 I 0 UJ 0 w w 0 X UJ 0:: 0 0 UJ ..J ..J <t :::> 0 UJ 3t ,..-g "- ,- - - - 50,000 40,000 30,000 20,000 15,000 fO,OOO 1.1 2 5 RECURRENCE INTERVAL-YEARS SUSITNA RIVER AT GOLD CREEK HIGH-FLOW FREQUENCY CURVES JUNE 10 20 50 FIGURE E.2.23 - - ~ 0 70 60 50 40 30 20 0-10 0 0 .... (.!) cr ~ 100 5 90 (/) Ci 80 70 60 50 40 30 20 10 1.02 1.05 2 5 RECURENCE INTERVAL-YEARS SUSITNA RIVER AT GOLD CREEK HIGH-FLOW FREQUENCY CURVES JULY AND AUGUST 20 50 FIGURE E .2. 24 - - ·- - - - ,..-' - 40 30 20 10 9 r- a r 7 '- en ·s LL. (.J .. g-5 Q LIJ (!) a: <( :I: (.J en SEPTEMBER 1.02 1.25 2 5 20 50 RECURRENCE INTERVAL (YEARS) c 20 r-r-----~---------------.---------,-----.---.~--~----~ 10 9 8 7 6 5 4 3 1.03 OCTOBER 1.1 2 5 10 RECURRENCE INTERVAL (YEARS) SUSITNA RIVER AT GOLD CREEK HIGH·Fl.DW FREQUENCY CURVES SEPfEMBER AND OCTOBER 2025 50 FIGURE E.2.25 --] 14 13 12 II 10 9 u 0 -8 lLI " • I~ n: 7 t : ::::> I-I I <( I a: 6 I lLI ~ Q. :=E 5 I I IJ.I I I-I 4 ~ I . 1.1 3 f" If r" 11 2 I v ) ~ I I .,j 0 MAY f • I I' d I I 1 ~ I I • I I I d ' !JI I I I I I I I •• I 1 f I It I ~ l l I I I I t H 11 ~ JUNE l • • • • JULY AUGUST SEP. SUSITNA RIVER WATER TEMPERATURE SUMMER 1980 LEGEND: ------DAILY AVERAGE VEE CANYON -+-DAILY AVERAGE DENALI e DAILY AVERAGE SUSITNA STATION (SELECTED DATES) OCT. FIGURE E .2.26 1 ~""' ,..., IJJ a:: a:=> IJJ ~-,,......, > 0::: CD -IJJ ~ a::: a. c:t2a:: z IJJ 11.1 1-1-2 -2 en a::::> =>I.Licn en!--<t ~ - - - N 0 - <( :::i z <( ~ z <( I.LI 3: 0 1-~ <( I.LI I.LI (!) (!) <( <( a: a: I.LI I.LI ~ ~ ~ ~ <( <( Q 0 + I • CD ( ~o) 3Hn.l'1M 3dW 3 .J. N a.: I.LI (/) >- ...J ;:::) .., I.LI z ;:::) ., >- <( :e ,..... "! N 1.1.1 1.1.1 0:: ::I (!) Li: 0 0 12 10 a 6 Q. 4 ::!l llJ 1- 2 0 ) } SUSITNA RIVER AT WATANA WEEKLY AVERAGE WATER TEMPERATURE 1981. WATER YEAR LEGEND: 0 WEEKLY AVERAGE TEMPERATURE II ENVELOPE OF WEEKLY L.:...J MAXIMA AND MINIMA 1 l J -2L------+------~----~r------+------1-------r------+------;-------+------+------~------+------4-- 4 a 12 16 20 24 2a 32 36 40 44 48 52 W E E K OCT. NOV. DEC. JAN. FEB. MAR. APR. MAV JUN JULV AUG. SEP. FIGURE E.2.28 - -' 15 0 0 0 0 ---- I a; :E LLJ 1- -------------I a.: :::i LLJ 1- 0 0 I 0.: :E LLJ 1- 0 0 I 0.: :E ~ LEGEND ----MAXIMUM ----MEAN -------MINI.MUM 0 26 137 224 SUSITNA GOLD CK. VEE CYN. LOCATION (RIVER MJLE)-8/15/80 15 0 0 I a; ~ LLJ 1- 0 26 137 224 SUSITNA GOLD CK. VEE CYN. LOCATION (RIVER MILE )-9/15/80 NOTES I.) ALL TEMPERATURES WERE RECORDED BY THE USGS WITH SINGLE THERMOGRAPH$ AT EACH SITE. 2.)GOLD CREEK'S TEMPERATURES MAY BE INFLUENCED BY TRIBUTARY INFLOW AT THE SITE. 3.)DAILY MEAN TEMPERATURES COMPUTED AS AVERAGE OF MINIMUM AND MAXIMUM FOR THE DAY. SUSITNA RIVER-WATER TEMPERATURE GRADIENT FIGURE E.2.29 A •. J ) \ PARAMETER' TEMPERATURE °C . ' - 15 - 10 • MAXIMUM -MEAN 5 -• MINIMUM 0 . -~51-r u: ~~l1 h!, l~ ~~ R4 111' -.~ r:::.;:: *oBSERVATION PI' I T ,_.I 'P -1 I~ I..,... T T I SUMMER :WINTER BREAKUP D-DENALl V-VEE CANYON., a~ GOlD CREEK 0-CHULITNA T-TALKEE:TNA ~-8UNSHlNE 88-SUSlTNA STATION A. Shall not exceed 2Q°C at any time. The following maximum temperatur.e shall not be exceeded where applicable: migration routes and rearing areas--15°C, spawning areas and egg and fry incubation--13°C (ADEC,1979) Established to protect sensitive important fish species, and for the successful migration, spawning, egg-incubation, fry-rearing, and other reproductive functions of important species. DATA SUMMARY -TEMPERATURE FIGURE E.2.30 ""' r ~. -' !~ Fourth of July Creek RM Direction of Flow l - Sherman Creek . • oa 011 Indian River Slough \ Talkeetna: 26 River Miles RM I Devil Canyon: 7 RiYer Miles I -< Slough 20 ' 9 ~ Slough 19 0 II Direction of Flow RM = River Mile Ryan Surface 0 Ryan lntergravel 18 YSI Surface YSI lntergravel \7 v Location map for 1982 midwinter temperature study sites. Datapod Surface 0 FIGURE E.2.31 Datapod lntergravel fJ SLOUGH 21 SUSITNA RIVER ABOVE PORT AGE CREEK (RM 142) CAM 149) 111.11 6 1!1.11 I"""· '"' AUG 31-SEP '"' AUG 31-SEP 6 u a.11 u 12.11 v v 1!.11 11.11 Q. 7.11 ~ 111.11 ,_, I: 1.&.1 1!.11 w 9.11 t-t- s.11 8.11 I I I I I I I I I I I r;,... IH011 111118 1111111 22811 IH011 10&8 111011 2211111 a.11 SEP 7-13 12.11 SEP 7~13 '"' a.a '"' I 1.11 -u u v v 7.11 111.11 Q. 11.11 c.. a.11 I: I: .-1.&.1 s.11 w 11.11 t-t- 4.11 7.11 I I I I I I I a.o~aa ·-HJiiiGJ 22Ba a-4119 10'111 1eaa 22911 """' 9.11 SEP 14-20 11 .a SEP 14-20 '"' a.e '"' 111.11 u u -v 7.8 v 9.9 Cl.. 11.8 Q. a.11 I: I: w s.a w 7.0 -1-1- 4.11 11.11 I I a-411111 IBGe 18119 22811 a-~ee 1009 18911 2228 -s.a s.a SEP 21-27 SEP 21-27 '"' 7.8 '"' 7.9 u u v v 11.11 11.11 f""', I 0.. 5.9 0.. s.g z l: w 4.9 w L9 1-!-- 3.11 3.9 9-408 1111111 1eae 222Q liH08 1 aae 11181iJ 22011 TIME TIME .._ FIG ORE E.2.32 Comparison of weekl_v diel surface water temperature variations in Slough 21 and the mainstem Susitna n· nlVer at Portage Creek (adapted from AOF&G 1981 ) . 14 13 12 II 10 9 ~8 UJ Q: ::I 7 ~ 0::: UJ a. 6 ::E UJ t- 5 4 3 2 ' {\ v\ ) ' 0· 1\ I . L i I \ \ !"·,; f -v 1 ' • "' \ ·~ r . \ /"'\ I \} \\ 'v I \ "'""--\ I 'i ' I \ 'l\1 \ I \ . ~ ' I ~I " I \ I . ,., "' '~ I, fJ . . I '.,/"' \,., \ ;1\ir",.V/ ' ,.......-rl "-JI V \ I . I \ f \t J '" • ,,...,..., 10 20 30 10 20 31 JUNE JULY 10 20 AUGUST ) SUSITNA RIVER DAILY AVERAGE TEMPERATURE (BASED ON PRELIMINARY DATA) -• -INDIAN RIVER DAILY AVERAGE TEMPERATURE {BASED ON PRELIMINARY DATA FROM ADF a G) ----PORTAGE CREEK DAILY AVERAGE TEMPERATURE 31 (BASED ON PRELIMII)IARY DATA FROM ADF a G ) 10 20 SEPTEMBER 30 SUSITNA RIVER, PORTAGE CREEK AND INDIAN RIVER WATER TEMPERATURES SUMMER 1982 FIGURE E.2.33 J l -} ] } -------------, --------------------------------------------~------~-------------------------------1 PARAMETER 1 TOTAL SUSPENDED SOLIDS, (rng. /1.) ~~-~~~~~~~~~~~~~ 6000 ----· ----H---if-+-lH -I--1-4-+-1-H-H-+-!-+-I+l-+-t-H-H-+-I+-1+1-I--I-H-H-+-1·--I-I-H-H-H-+-I-I J-1--1-J-f-J-f-1--1-1--1-H--I 4000 • MAXIMUM -MEAN 2000 --... .. ---··----- •. MINIMUM . ---... ------~-,;;~-·-------·---1-+--11--f-1 --. ----·--1--H-+-~-1-.. ,. .. - 0 -· --T -t--+-+-++-1-·-----.. --. -------+--HI--+-+ -1---l--t-~- ---~ ------. -.•. ---· ----------------------- - ------t-+-1-+-t· ~FOBSERVATION ·. ··••··5~:. •at .. l.:5··-t·;r= ;~.~{:t·~· ~·.~ ·;~ ·;·J:>l~f:i~~:~.~~ ~> -.. ----------·------------~------ SUi\.rlMER :WINTER BREAICLJP 0-DEUALI V-VEl: CANYON G~ GOLD CAEI:K C-CHULITNA T-TALKEETNA S.-SUNSI'IINc SS-SUSITNA STATION No measurable increase above natural conditions (ADEC,l979). Established to prevent deleterious effects on aquatic animal and ·p,lant life,_ their reprod~ction and habitat. f DATA SUMMARY -TOTAL SUSPENDED SEDIMENTS FIGURE E.2.34 -... --· l J ~J I -· "1 ' --··-i J ·-l ' \ 5 4 i-t: I 3 1-f-1·-. i- ,s~ )lh" ~~ r-~U 1--- r.:-. 1---~f. .-IO,OQO ...... l/ 1/) 9 -8 r::= u ~ 7 Jc;:; m F-i-- w 6 (.!) a:: 5. <t r-:r-:r 4. 1-1-· u ,_ If (/) F -J-0 3. J •. i-f-1-· t= 2. I/ 2 3 4 5 6 7 8 9 100,000 1,000 3 4 5 6 7 8 9 2 10,000 SUSPENDED SEDIMENT DISCHARGE <TONS I DAY l SUSPENDED SEDIMENT RATING CURVES ' UPPER SUSITNA RIVER BASIN ., 'j·' II II 2 ) fi:. ~i~m:1+1: p,: kr l:'t; · , I+ ---. ·1~1~~u,~ II r f~!!~J: kfi,, ii I Hi Ll =. 1'4F'' c··· '" 1-t ". H ;1r .;r, 1~ r n p~;;: i+i' ' II II l-~tfiiH WJJ I I ' I ! ! ::1 4 :. J J 111 t· "' 1: H : t-,, ' ' ' d . :: .. ~. ' ' I ' ' 6 7 I' ·' 9 1 FIGURE E.2.35 -~ ) -J f tU .LUL !~--... 1.. I w= ... -., .... ":l-" · .. 'l' i .. • .... ~: .... "·:!. I . : r··· .. .,_. =~::~-:-~ ~~:: ~-:!-:·· I· . : : ~. ·.: ~:'!-· . ..-! i .: -~--~ ~: .:.·: ::.1. -_,. ; :~: 18.5r:-;-~-:-:-:---~ --t----~ -:-:-------'-----~ ----r--1-•-r--r--:·+--O...-,;;;-·r----.. __ --.·-·.· · .. · ·.· ...... j.: ·, I . . I· ..... ,::· .:11 ~ . . ~ .. ! . '. ; lf'7'. a. . . . .. . . ___;___ ' i--1--• : : .. : :. . . . : : . . . I . . . ; . : .. 1---,_ . ·-·. . .. . . ' . . . i v .. 11 ~i~j~f t~f-~ SUSPENDED SEOII·IEIIT SIZE AtiALYSIS . ~.: j:~:: :: .. 1 : J:'_l; ! 1 ~: ~;-Hli~: LEGE tiD STAT ION ... . .. . L.. . . V! /~ e& ______ SUSITNA At GOLD CREEK ---t--,-.-. -,_--j~fil-t~~ -· ·- :~·::z~ ~~:: ___ ---SUS I TNA Near CAIITI'/ELL j_j I :: V. · ;'t. ao . .. .... ___ ..:::!...._ SUSITtiA Near DEtiALI --I r ~-~-_,.7"'-;-:1-1-ll-1--t-H ~ . ::: .. . -----MACLAREN Near PAXSON --r.::t--.1 ______ ......... : ..... :c .... __ •. ii) ...... :·,---·. :. t--1--' : ~T·~--. .. ... : ·: ..._.,} ·---~~ ... ·t- o 10 • • . . .. : .. : ,, __ -.•• -·~· ... f-" ..... ___ :-:(..;, : r .,,-w : j I i ·.:: :1· ~ r-t:t 10 ~-. . ---. -.1 --;-~---:-~-·----1--.---.---. -i--+--i,---t--:--t-:-+-j.l<· iFt--t-+-~,-:: ....,...,7'8 J.:J"'·· -t-------1~, ---· -t-o _, . -.. -. ·_ .... I: .· i· I · .. · . I : : :· : v r-:f: ... ~. I . I i I ; . i5 so . . ... .. .:::r· i ..<:...:_ !-!;~.:::---. 1.-'-~ .: ~--r-~ . -·.. : · i i i :: I . . . · b-1::::-~ .~f!f ~: l i : !JEI-t-t-+-t--i 2: 50 . ' i . : Ji:::: ~.-r-.:t;;.-7.~ : : I : I -~ 40 :I . -:-I ...;-~~~~~~~--: t+ f-.. : -,· ' . :, . -jf--+-1--+-t- t-... :::. >I i I . ..-:~f".: ... ~ : : ; .:. :: . 0:: 30 _ -:-· ~·y.;;_;o.-· . ; ..... 1 . . ~ . ·:·1 ~-~~~.Y;"'! 1 i-' ... .. ·: ::: :: -! - ~ "~ le"i~-::f i .. -ifL. ~ ::· L-: :;: : .... Hf ""'" . _,. =-+= -c"j' ' -: I-~ r-_-:_ ... -.. 1 t--:.t--_r-_1 ~ 10 • I ... : ... ·:·I i i: I ' . :·~·:: ... ·.t·.: i . w .. !.:-. . ·: .. · I .· : : . . :· ' i . I. • • • I I ! ll. •-.---1-r··-f-· -----l-1· -!--1-r·-1·-------··---......J..-r-~--~---r-· ~ ~ p ·-.. ·-· .. ----· .. .. ' .. · · I · I · -tt r-11~. -~!i ... . ... .. _!~: . .. I : .. . INTERIM REPORT . : :!1i• :: :: -·.-·••. •• . . ··-' .. ·_ . . • • ••.• •••. I [··-· . . . SOUT~~~~~R:~A::~LBELT I· :: ~l~mj lfi< ·f = t .• f -.-[, ~~; ; : ': -7't .t7 c~: '.---.~-0-~L...,p~-S ~-3-~,E-~-:-~:~-~-~-;-:i""'l'"'~"AS-r!--:-1; "":"""11 O. 1 0.001 I .01 .I 1.0 PARTICLE SIZE IN MILLIMETERS SUS PEN OED SEDIMENT SIZE ANALYSIS SUSITNA RIVER FIGURE E.2.36 l ( l l -------------·-----------------------------------------------------------------------------, ' 1500 0 - PARAMETER; TURBIDITY I NTU •I·~ . ----· ----· -----+'f'-il11fCiHPEB-1-t-l-l-l-lc...;.....+~ 1--H-t++f-+t-H---1--J--I-i -----· ·· .. H-F-1.-'F-~f-t-iH . -----_, 1-f-++++--H- -.--f-+-1--+-l------ SUMMER ·WINTER • MAXIMUM -MEAN • MINIMUM "*"oBSERVATION r· ~ --1-l-l>tLI1++-'f' Is~ BREAI{UP D-DENALI V-VEe CANYON G-GOLD GREEK C-CUULITUA T-TALKEETNA S-SUNSHINE: SS-SUSITNA STATION Shall not exceed 25 NTU abov~ natural conditions (ADEC, 1979) l::~;taLJl.i.shed to prevent the reduction of the compensation point for: photosynthetic activity, 'which WilY have adverse effects on aquatic life. ' DATA SUMMARY -TURBIDITY FIGURE E.2.37 ~ ~~{;> - !00 90 so 70 60 50 40 ::J ~a t-'" :z: - 3 2 10 -- -~ ~-. 1· r --. :-=-i-~--=----r-:-::- 'H; •· • ; 1 ' ' 2 3 4 5 '.6 7 8 9 100 2 3 4 SUSPENDED SEDIMENT CONCENTRATION fmg/1) ' 5 .... ''I ~ ===~-=' -,~E2=~~i • :: T-:;:t t; -,..:;;: ::; . .cr=£~ ' 6 7 8 9 TUJ:;BICITV VB SUSPENCEC SEDIMENT CONCENTRATION FIGURE E.2.38 .... J l ) 1 PARAMETER• TOTAL DISSOLVED SOLIDS (mg /1 ) • ---- 300 - - • MAXIMUM - - -MEAN 100 -.. - -•. MINIMUM 0 . - p ~ r. ~ II :r<;.j o, ·3-~,~( ~-.I~ 15 l -J. · . .J.· r I{J ... I"+' I T 1~1 '!' *oBSERVATION ----.--.J SUMMER :WINTER BREAKUP D-DENALI· V-VEE CANYON., a-GCH.D CREEK C-CHULITNA T-TALKEETNA ~-SUNSHINI: SS-SUSITNA STATION A. 1,500 mg/1 (ADEb, 1979). Established to protect natural condition of ~reshwater ecosystems (500 mg/1 is the cricerion for water supplies). · DATA SUMMARY -TOTAL DISSOLVED SOLIDS FIGURE E.2.39 I .~----1 J ) PARAMETER• CONDUCTIVITY, pmhos/cm@ 25°C · -·· -1-+-le.++--l-J.-H·+++4-H-H-I'-++++++++H-~1-H-+1-+l-++.J.+-1-.J. Hf-++++-H 400 ..... ---•·· --l-f-1--l-1 ++·•1-1-l 300 • MAXIMUM -MEAN 200 ----·• -++-~-++-!- • MINIMUM . .. .. -+-+-H-t wo ~-1--+...f .. .. -- -· ·--· --~-.. -. .. -···------·-- *oBSERVATION . -------~ -·---.. ... -.. -- -··-----·-. -·-······ ···----·-: ....... -~+~·+-~'-······-- · ·· ·1" "I . ....,,-,r.·lc--· 2'1--·r-·---~".1--, ~2 ~~~t---·-\---~-----~-_-'·r· "'2 ~- •·· ~·--~ ~ . ~--. = 1-1~.: .. ~-. :-, ~f -"~ ~ --1* =_·--_: _( _ _-_: ~~ --4~ -·~ ·: :·~ -~ ~~ -~ ~ff~~-l -·H ~ . :~+-~t:t:.':-~E:!j~+-t-+=S·I'-5 ~---t-1 SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON, a~ GOLD CREEK c-CliULITNA T-TALKEETNA $-SUNSHINE SS-SUSITNA STATION No criterion established DATA SUMMARY -CONDUCTIVITY FIGURE E.2.40 . l l ... J. } ------·------------------------~----------------------------------------------------------~ PARAMETER 1 CHLORIDE, (mg. /1.) t A 30 20 • MAXIMUM --------+-l-+-+-1--l--1'-+ -MEAN 10 t-t-~+-i-i· . ·• . - - . •. - ---·+4--1-......_,H • MINIMUM ---~·-1-+-l-+-+-+ ++-+-~+-!-- - -.... J--J-1--l--ll-l--.J. ···. ~ . 0 ' T --+-J--l--1-1·· --· · - tt=oaSERVATION -·~ -. ~ --. --··-... ----------. . Itt ~lc rr~~ ~1l;i <; ~/ ~~: I< .• ':~:~ =;~:: • ~ :=. /. 1~_:: l :sS .. SUMMER • WINTER BREAI<UP D-DEUALI V-VEE CANYON a~ GOLD CREEK C-CHULITNA T-TALKEETNA S-SUNSJIINE SS-SUSITNA STATIOU Less than 200 mg/lx (ADEC, 1979) Estublished to protect water supplies. r OAT A SUMMARY -CHLORIDE FIGURE E.2.41 ""] . "-'1 --'] ') -· -~1 ) ----.~ ): 1 I I '· PARAMETER: SULFATE, (mg./ 1.) ·---.. 1--J-J-4-1--l- t 1-- . . -· -I--. -· ... J---. --1-+-++~- A ·H-IH-++ .. ---...... - .. - -.. ·--·-++-++-!-+4-t . .. -----· ----1-.J..-I~.J-.J 40 ---· .... ----~-1--1-·-~·H-11-H-1--1-t--f-t--f- -· ....... ··· --+-f--1-1-1-+-+++-f-++-+-·1-1-H-1-1-1-HI-H'-+ J--1--f--f--f--H-1'·+-1-++ · -· · · -· t--t-~-+-~-Hf-t--1 l-+--1--1--1 ,--~---- • MAXIMUM - MEAN • MINIMUM ~-. -~~ TL :,~-.: *oBSERVATION ~ -~ ~-= ~ ~ · ~~IS~ _ · SUMMER · WI~Jl-ER BREAICUP 0-Dt:NAL.I V-VEE CANVON G~ GOLD OREEK C-CHULITNA T-TALKEETNA S-SUNSUU~E: SS-SUSITNA STATIOU A. Shall not. exceed 200 mg/1. (ADEC, 1979). l~:,;t3l)lished to protect water supplies. DATA SUMMARY -SULFATE FIGURE E:2.42 } 1 1 1 --, ---1 -~-1 .. ~, __ / -~ 1 ) 1 l -----------------------------------------------------. PARAMETER • CALCIUM (Ca) DISSOLVED, (mg./ l.) ------ -· 1-H--1-+--1-+.t-t--H-l-++ 60 ---------------+++-1-l -· -· ----·---- ----1-4---1--f-.:l------ . --1-4-!--l-l ---- --tc+-t-+-1-+ 40 • MAXIMUM - . ---- ----~-l---1-+-+- + -····· --- -----1--1-1-+-1--+-1~ H-lf-++-H-1--H--1-H+I-+-1--.J--1-l-f-,1-1--J-l-1--1-1--IH-~ H-t-HF-H-++-++-1+++-+-+-1----1-·1-H--I-1--l'--1--l-++-H--MEAN ---· ----·· -1-l-lH-t-+-+++-+-l-1-+-+ 2.0 · - ---f-l-lH-1-+ . -... ---- -------- ---!-4-~1--1---l-1--1 ·---. --• • MINIMUM -l--+--1-t-+·----·- 0 --+ ----~---·r - -~ - ----+-1---1--1-+ -..... --·· -··-- -... - ----1-4--~-+--l--1 :ft=oBSERVATION I .. L ~7~f=T~::-5S E __ 25._-::-_-___ :~:33·~~ __ ;;\. 4-~~-:.._1-=--J_~C:: _ ]~ 7__~ . ! -I\ --lr ( ·ffF-~ -['f ~ ~ ~ ,L __~, ::-: :i1-I (_ . = ---f -~ ---·-_ -::--_I_ --_ --+---.... -+ - -s:;,~ - '--.•. .L..J....L.L....L.J.-.l---L.L..L.L....l....J_LJ..._l-J_l_J,_J_...L.J_.l.-1-1 SUMMER :WINTER BREAl<UP 0-DENALI V-VEl: CANYON G~ GOLD GAcEK C-CliULlTNA T-TALKEETNA ~-SUNSHINE:: SS-SUSITNA STATION l~o cr L tcri.on established I DATA SUMMARY -CALC I Uf·1 (d) FIGURE E.2.43 1 ---------------------------------------------------------------------------------------, PARAMETER 1 MAGNESIUM (Mg) DISSOLVED, (mg. /l . ) ·r- -1---·----1-.. ·-·· --- -··· ·-··· ·· ·· -· 1-· -·--!--+----·· --I-·--1-t-··· 1---· 1-··--··I----- --·----++-l--1-I----.. -----·--·--+----... .. 1---··+· --·1----··· ·--1- ·+·--....... . I 0 ... - -··+ t·++·-~H +++-++++H--4H--I-+++++l--+++-+ +-l-+~--I---1H--+++++++--+++-1--I-+-If-H--H+++++++-+-t-HI-H-H -. ·• ------}-+-l-+-lf-.f-l-+ -+-+-+-l--1-1---·--·-·---·f-f-1-~+ -.. -. ·-- --+-HJ...-1-.f -H-·1-t-t·· .. --... . .. .. 10 • MAXIMUM I· . . . .. -... -1---1--l-1--+-H-+++.J--l--cl-f-1- -MEAN 6 +-i-t--1--1-+-+-+-1------- '-t-+-+-t-1·--·· .. --... . -1-•. 1-""------·--·-·····--------•. MINIMUM 1-+-.L--t-+..&. I -------- t-+--lc-1-++ --...... -- ··· -· · -· -1-1-++-H 0 ·· ···--·· -~·++-+--1--l H--H-IH--i-+++++++-++-l-l-+-f-HH-+++++++-H-l-+I--Hc-H-1-++++++-+l-f-H-11-H+-I-11-+-+++++-1 ---. ----... --····I--1-HI--1-+-1- *oBSERVATION -..... --~-···---------------------· -------·-·--· . . ·--· . . . --. -. -.. ------- -·--.. . -·-. . ..•. .. -~ . ----.. . : I ~ !211. ~ >lL tJ -~~5~ =I~~ -f3!r--= -~ • = -=!1''~'~ -::1~~ ·4· ~ 22 _ -! ~ __ -II _ -L-J L ~ t~: .: .• 1....1... ... ID 1 ~ ~~ r ·· q. ·It -~ 1r =f~F ~ ~ ~1 , ~ ~ · :=tr ~-J ~ = _+:' ~ -1 : ~~ = -_ -1.L.·.~....--~J.....~:WJW.-~ Ll-,Ll--·-....~. ~~....1.-· ....1.---'-:..~.-=..J...--...~...-...~...~J_~~§J_~~-=L-J SUMMEil ·:WINTER BREAI{UP D-DENAU V-VEE CANYON a~ GOLD (Hit:EIC C-CI-IUUTNA T-TALKEETNA S-SUNSHINe SS-SUSITNA STATION N1.J cr-iterion established. DATA' SUMMARY -MAGNESIUM (d) FIGURE E.2.44 ---------------~------------------------------------------· PARAMETER: SODIUM (Na) DISSOLVED, (mg./ 1.) --I--I-- --· -+--. ----1---t- ---t-------l--1----t-+-1-t--t-t--1-- ---f----------+4--------t-· -+++-+-H ------1-----1---1-1-t--1-1--~~f--1 --.. ------·-t-------------- -----+ -----+ ---I- 30 --------------1---l-+-+~-++-+---1-+-+--1-1---+-+++-+-+-++-+-+-H---jl-l-1-~-+++-t-1---+-+f--1-J-I-+-f--l--H 1--.. 20 • MAXIMUM ------------------------------... -------+--1--+---1-++-+4-4- --l-+-+4-++ ---· --- -----1-t---1--1---1-t-H-------f---t-l-1-11-+-f+ -MEAN -·----++-H-1--++ 1-Hf--1-1-t-t--1-+-+-+ 10 -It--.. --~---· ---~ ----. --... ~ --.. ----·. ---• MINIMUM ·-·--------------'"' -- ~------~--:-~.-l--. 0 1 ------- ------.. --------""" ----· ----·-----. ----·-.. -. --· --·-· ·-·----------------H-1-+1-~ -----. -.•..... ----... --· -... -. --· ------·· ----------------· ----------· ---------- 1 -= 12 •. :_· ~ --. t --: ~~ l~_ -~~~ ~---:: --: -~ --26 --~~ ~--. il..< =·l-~-~ _-= ~ : D = .. . --" -_ :·I --~ l L I _ ~: _ ~ -j '' : T -I -"f( lf. = -~r:: :~ jL ~I 111 ·jl--t~ --=--l =-1~-::---::-:' ~ ~ -r~ ,= ~ ::-= -t= -j~ = : -- SUMMER WINTER BREAI<UP Ll-DEtiALI V-VEE CANYON G~ GOlD CREEK C-CHUliTNA T-TALKEETNA ~-SUNStiiNE SS-SUSITNA 'STATION '*OBSERVATION !Jo c L"i Ler ion established. I DATA SUMMAilY -SODIUH (d) FIGURE E.2.45. 1 -J 1 ------1 ----] ------------------------------------------------..,.-------------.., PARAMETER' POTASSIUM (K) DISSOLVED, (mg./ 1.) l----1-4--1--1------- ·-------·-.. --------________ ,., --· -- .. -------------. ·---. -.. .. 1--l---lf--¥-4 l---1-+-1--l-----------· -t-t-H---t-1-++--f-t-f--t--1--HH ----------. -·-------------·--- 10 ---------~-t-+-+-4-l----l__..-+-"-++-~H--11--H-H-++-1+-1-• MAXIMUM --------------t-1--+-+-t-t-f HH-I"~t-t--1--t--HH-t -1---H--l--1---IH-1-H-H-+++-f---}-- --------,-!--+-+-+-! t-f-1-+++-+--1----· ... --. - --. 1--MEAN - - ----·--·--. --f-.1--f-+-.J-.-I--IH-+-+-1-- -- -1--+-lf--1--1-· - -· --H-1-~-t-~- 5 .. ~-·-· ----------~ ------------- ·--· -----------·---------1-+-+-l--1- - ---· • . MINIMUM ---~---·-··· -----------... ----· --- . ------f--- - --·--· -~ --- -- -·-----------· --- ------·------ 0 ----------.. ---.. -----·--.. ---....... ·-----·--· ---~ ---- ----·----.. .. --'·-~ --.• - -----.. ------------------- ----. -----*oBSERVATION SUMMER :WINTER BREAICUP U·· OEUAll V-VEE CANYON O~ OOLU IJREEK C-CHUliTUA ,-... TALKEETNA ~-SUNSHINE SS-SUSITNA STATION No criterion established. DATA SUMMARY POTASSIUM (d) FIGURE E.2.46 l ~----------------------------------------------------------------------------------------------~ A PARAMETER I PH l. . - - ---·!-++-•-+--•- . ·-·-·--·---1-+-+-+-t ----·-t-t-f-+-t-+--1--t-1-+t-4-1-+t-t-•....f-1 8 • MAXIMUM -MEAN ---· I 7 - 1--··---·-· . -1-.. --· . • MINIMUM t---· -1-+-+-+-t-----· -··--· .. -·-- . -.. *oBSERVATION 1 P ·-~~-··1!i -I i ~ t: -l I~ : - --., . I I' . T . Cj;· ... ,~ ·. -t .11' .. -;~-.· - ~ ""25 -~:~J i:·-41. -~{~ -£"1~:·~~]~~.1~.:-l f~ · -· ---··· .-l -l$ = :. · ~: · ~--· ~ ~-_c -~: · E'""·;_ -· = -~--= 5 ~ ··· -· SUMMER WINTER BREAI{UP D-DENALI V-VEfi CANYON G-GOLD CREEK C-CliULITNA T-TALt<EETNA S-SUNSUINIS SS-SUSITNA STATION A. Not less than 6.5 or greater than 9.0. Shall not vary more than 0.5 pH unit from natural condition (ADEC, 1979). Established to protect freshwater aquatic organisms. DATA SUUVIIVIARV-PH FIGURE E.2.47 1 l 1 PARAMETER: HARDNESS, as Ca co 3 , (mg. I 1.) no ---------· ---+-t-++--f-+-t J20 • MAXIMUM f-t-+-t-+-1---------· ------ ----1--1-4-I--+-JH--11--1 ----·--- --· --1-+--1--1444...{----1--1---MEAN 70 -+-t-+t-+-. - - - -1--l-1-"t"+-+-----------------------t-t--i-+-+-+--+- • MINIMUM 20 *oBSERVATION SUMMER • WINTER BREAl(UP D-DEUALI V-VEf CANYON a~ GOLD CREEK C-CliULlTNA 1·-TALKEETNA $-SUNSHINE: SS-SUSITNA STATION No criterion established Some n1utals have variable synergistic effects with hardness, dependent on the prevailing, !J,!rdtt8Ss in the water. 'l'he. criteria fqr cadium, for example, is 0 .. 0012 mg/1 in hard water and 0.0004 mg/1 in soft water. DATA SUMMARY -HARDNESS FIGURE E.2.48 1 12.5 75 25 -"l ---] PARAMETER:_ALKALINITY, as CAC03, (mg./1.) +++-J.-+-J...-4----· . ---++-.J--1--1-+-1 ---------+-++-+++ .. -------.... -·· ·-··1 ·-1--t-+-+ -·--... --... -1--+-1-t--1------·-· . -· -. ·---- . ----++++++++++++++-!- -... -+- .-t.-t-4--1-l-W------- . .. ---~--.. ·-- -----1-++++++-++-+- --t- -H-H-+-1-+-f-+· · ---· -----· - --H-H-H+-1 -~ --· 1--l-1--1-lf.--~---- --+r·-+-+-!~-+-+ -· --- . ---1-+-J-.-1--t-4..-1-H --1-~;...-t--1--l--l~~~----· -·----+· .J--1--1-1-If-1-+--· ·----... -------·-· · -1-+++.&.+++-H-+-- . -----1--1-t--1---1- -+-+-t--1-1--1--1--~--------- ·-·--------------f.-'-- ·_· :· 1 ---l~ ->-L2r~ -t1~ -- ·I[) I -t "'--H+:: -l-IT -= SUMMER -· ---· --1-.J-+-+-+---... -·- ---· ·--t-+--1-1--+- ++-f-.J-+ · ----l-+-H--1!--t-f-+t+++ ·WINTER BREAI<UP 1 • MAXIMUM -MEAN • MINIMUM *OBSERVATION 0-OEUALI V-VEE CANYON a~ GOLD CREEl< C-CUULITI~A T-TALKEETNA ~-SUNSHINE; SS-SUSITNA S.TATION 20tn(!,/l ~!E_rno!:~ except where natural conditions are less. (EPA, 1976). t~::c; L,llll..ished Lo protect freshwater aqua Lie organisms. DATA SUMMARY -ALKALINITY FIGURE E.2.49 -1 --] l ] PARAMETER • TRUE COLOR, PLATINUM COBALT UNIT · ---··· - ---· --t-1-f-t-+ --l-+-+-+-+-+-+-i-+-+-+-l-H--t-+-+-i--1-1-+-l--l-1-1-+-l-+-l-4-1+--t+-I-+-I-J-.-I 150 ----- ----++-1-+-lf-I H--IH-!H-+-+-+-1-·· ··• · ----+-+-1--H - - - --· - 100 • MAXIMUM . .. ---- --1-+--t-1---t-1-- -f--H, --14-1--1-·++-1-4- -MEAN A---.:o-so 1-1--i·-1-1----- - --1--1--l-J-li-l l-~-1---H~H-+-H·-+++++-1--H-H-H-H-H-H-~-1--1-+-H----J-+-1'-+-1-4- --... -•. MINIMUM ~· -··--... .. ~-------·---~-.. -· -· ·-· 0 - - -. -1-+~--1-1 ---1-1--f-+--f- -f-+++-1-- - ---------------------. · ---------·--+t-H-l-HI-l *oBSERVATION : WINTEB BREAI·(lJP SUMMER D• DENALI V-VEE CANYON a~ GOLD CREEK C-CHUL.ITNA T-TALKEETNA ~-SUNSIHNE SS-SUSITNA STATION Shall not exceed 50 units (ADEC, 1979) Established to prevent the reduction of photosynthetic activity wh_ich may ha.ve deleteriou~ · cff~cts on aquatic life. ' OAT A SUMMABV -TRUE COLOR FIGURE E.2.50 2 B-7-0 -] l PARAMETER 1 ALUMINUM (Al) DISSOLVED, (mg. I 1.) - -----. -f-f-+++-+--1-t-f------· -- SUMMER WINTER • MAXIMUM -MEAN • MINIMUM I *oBSERVATION BREAKUP D-DENALI V-VEE CAN'VON. O~ GOLD CREEK C-CHULITNA T-TALKEETNA S-SUNSHINe SS-SUSITNA STATION A. No criterion established B. A limit of 0.073 mg/1 h~s been suggested by EPA (Sittig, 1981). This suggested limit is based on the effects of aluminum on human health; DATA SUMMARY -ALUMINUM (d) FIGURE E.2.51 1 PARAMETER' ALUMINUM (Al) Total Recoverable (mg./ 1.) 20 • MAXIMUM -MEAN 10 •. MINIMUM *oBSERVATION H· SUMMER WINTER BREAICUP o-DENALI V-VES CANYON G~ GOLD CREEK C-CHULITNA T• TALKEETNA ~-SUNSHINE:: SS-SUSITNA STATION A. No criterion established B. A limit of 0.073 mg/l·has been suggested by EPA (Sittig, 1981) This suggested lii:nit is based on the effects of aluminum. on human health. DATA SUMMARY -ALUMINUM (t) FIGURE E.2.52 1 1 ] 1 ] PARAMETER' CADMIUM (Cd) DISSOLVED, (mg./1.) 0.003 HHHH++~HHHH4+++~HHHH++++~HHHH4+++~HHHH++++~HHHH++++~HHHH++++~ • MAXIMUM -MEAN A > O.OOI~~~~it~+t~~~~~~~~+t~+t~~~~~~~~+t~~ • MINIMUM A-?-B~ ~-HH~1~~++~~++++rr~HhHHHHHHHH4444~4+++++++++++~~~HHHHHH44~44~ 0. 000 1-H1-+++-t--l-'t"Hf-TT-t++t-H-t+-i--H+++++-+-H-4~.......r-+++-t-1.-H-+-+++++++-1-H-H++ ...... ++1-HH-t-++++H-1 *oBSERVATION SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON a-GOLD CREEK C-CHULITNA T-TALKEETNA S-SUNSHINI: SS-SUSITNA STATION A. 0.0012 mg/1 in hard water and 0.0004 in soft water. (EPA, 1976) B. Less than 0. 0002 mg/1. (McNeely, 1979) Established to protect freshwater aquatic organisms, DATA SUMMARY -CADMIUM (d) FIGURE E.2.53 } PARAMETER' CADt1IUM (Cd) Total Recoverable (mg. /1.) 0.02 • MAXIMUM -MEAN O.OL • MINIMUM ~0 *oBSERVATION SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON a-GOLD CREEK C-CHULITNA T-TALKEETNA S.-SUNSHINE: SS-SUSITNA STATION A. 0. 0012 in hard Hater and 0. OOOl~ rilg/1 in soft ·water (EPA ... 1976). B. Less than 0.0002 mg/1 (McNeely et al, 1979). Established to protect freshwater aquatic organisms, DATA SUMMARY -CADMIUM (t) FIGURE E.2.54 J J 1 1 l PARAMETER• COPPER (Cu) DISSOLVED (mg./1.) 0.02 • MAXIMUM -MEAN 0.01 • MINIMUM 0.00 "*=OBSERVATION SUMMER WINTER BREAKUP 0-DENALI V-VEE CANYON G-GOLD CREEK C-CHULITNA T-TALKEETNA ~-SUNSHINE; SS-SUSITNA STATION A. 0.01 of the 96-hour LC 50 determined through bioassay ~EPA. 1976). B. 0.005 rng/1, (McNeely et a1. 1979) Established to protect freshwater aquatic organisms. DATA SUMMARY -COPPER (d) FIGURE E.2.55 .... l -1 --1 J J PARAMETER' COPPER (Cu) {mg./1.) Total Recoverable a· 1 tttmmmttt~ttt:mmm:tt:t:t:t:1tttt=ttm:tt:twftttttt±:ttttttjjj:tttt±ttttl B .------?-0 t~HH~)H-f~rf4---~· ~IH-~I~f~l~~44~-fi+~~cf+~-~+.~~~~~~I~HY~~~+.+~++~H f-+-i-t·+-1--11.<--t -.. -. ·-. l Tl .-,~ --H-+f++-l-+++++·!!tt=~"t+-l-~-t-IC:::~I-1-1-1--Hl:).H~-Hli.++.{!;.-l-+=J:~ ~<;;ISHH SUMMER WINTER BREAI{UP • MAXIMUM -MEAN •. MINIMUM #OBSERVATION D-DENALI· V-VEE CANYON a-GOLD CREEK C-CHULITNA T ... TALKEETNA ~-SUNSHINE SS-SUSITNA STATION A. 0.01 of the 96-hour LCso determined through bioassay (EPA, 1976). B. 0.005 mg/1 (McNeely et al, 1979). Established to protect freshwater aquatic organisms, DATA SUMMARY -COPPER (t) FIGURE E.2.56 l 1 . 1 ) 1 -~ J PARAMETER' IRON (Fe) DISSOLVED (mg /1 ) • -~r[;· -'i. ;3 - 3 -- 2 • MAXIMUM ~ -MEAN •. MINIMUM - 0 . 1 *oBSERVATION '!' - SUMMER WINTER BREAICUP D-DENALI V-VEE CANYON G .. GOLD CREEK C-CHULITNA T-TALKEETNA $-SUNSHIN~ SS-SUSITNA STATION A. Less than 1.0 mg/1 (EPA, 197&; Sittig, 1981). Established to protect freshwater aquatip organisms. DATA SUMMARY -I RON (d) FIGURE E.2.57 l ... ,_ 1 1 l I PARAMETER• IRON (Fe) Total Recoverable (mg./1.) SUMMER WINTER • MAXIMUM -MEAN •. MINIMUM *oBSERVATION BREAKUP 0-DENALI V-VEE CANYON a~ GOLD CREEK C-CHULITNA T• TALKEETNA 8, .. SUNSHINE SS-SUSITNA STATION A. Less than 1.0 mg/1 (EPA, l976i Sittig, 1981) Established to protect freshwater aquatic organisms. DATA SUMMARY -IRON (t) FIGURE E.2.58 - J --~ --. J ] PARAMETER' LEAD (Pb) DISSOLVED, (mg./1.) ~0.03 0.02 • MAXIMUM -MEAN 0.01 • ·MINIMUM 0.00 l *oBSERVATION -H-1--1-+-1--l--1--:H--f-----.. SUMMER WINTER BREAKUP 0-DENALI V-VEE CANYON. G-GOLD CREEK C-CHULITNA T-TALKEETNA S_-SUNSHINE SS-SUSITNA STATION A. Less than 0.03 mg/1, (McNeely et al, 1979). B. 0.01 of the 96-hour LC 50 determined through bioassay. (EPA, 1976). Established to protect freshwater aquatic orgqnisms, DATA SUMMARY -LEAD (d) FIGURE E.2.59 l .. I 1 ~l l PARAMETER' LEAD {Ph) {mg.Ll.) Total Recoverable 0.3 ~HH44++~~HHHH44~++~~HHHH44++++~~HHHH444+++~~HHHH~++++rr~HH • MAXIMUM -MEAN •. MINIMUM A 0 J *oBSERVATION SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON G-GOLD CREEK C-CHULITNA 1'-TALKEETNA 8 ... SUNSHINE: SS-SUSITNA STATION A. Less than 0.03 mg/1 (McNeely et al, 1979). B. 0.01 of the 96-hour LC 50 determined through bioass~y (EPA, .1976). Established to protect freshwater aquatic organisms. DATA SUMMARY -LEAD (t) FIGURE E.2.60 1 ---j ---··] PARAMETER 1 MANGANESE (Mn) DISSOLVED, (mg./ 1.) 0.3 0.2 • MAXIMUM -MEAN 0.1 •. MINIMUM 0.0 ll l *oBSERVATION SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON a-GOLD CREEK C-CHULITNA T-TALKEETNA ~-SUNSHINE: SS-SUSITNA STATION A. Less than 0.05 mg/1 for water supp1y.(EPA, 1976). Established to protect water supplies. DATA SUMMARY -MANGANESE (d) FIGURE E.2.61 l l 1 -l 1 ] PARAMETER • MANGANESE CMn) (mg./ 1.) Total Recoverable !+-1----t-+-1--·1--1--t-+-++-H-++++++·H-+t-H--t-1-++H-++++H-H-H-H-1-+-11-+-11-4-lf-.Hi4-l -.... ---1--H-1--1--1-l--+-11-+-14-1-f-1--1-f -· -~--1.5~~HHHH44++++++++++~~~HH~44++++++++++++++~1-+-1HHHH~44++++++++~1-+-1~ ·1-l-f--HH 1-t--1-1-l-14--11-1-·· · --· • MAXIMUM -MEAN O.~'~++++++++++++++++++++++++++++++++++++++++++++~++~++H-H-.1--f-H-H-H-H-H-H-H-H • MINIMUM *oBSERVATION WINTER BBEAICUP SUMMER D-DENALl V-VEE CANYON a-GOLD CREEK C-CHULlTNA T-TALKEETNA ~ .. SUNSHINE: SS-SUSITNA STATION A. Less than 0.05 mg/1 for water supply (EPA, 1976) Established to protect water supplies, DATA SUMMARY -MANGANESE (t) FIGURE E.2.62 ---, l -1 ---0 'l --l -. j --1 ] PARAMETER 1 MERCURY (Hg) DISSOLVED, (mg ./1.) 0.0002 1+-jH-f-H--+++++-+-H-1 • MAXIMUM -MEAN • MINIMUM t--H-++-+-,>h~-·-r LJ } *oBSERVATION SUMMER ·WINTER BREAKUP D-DENALI V-VEE CANYON. G-GOLD CREEK C• CHULITNA T-TALKEETNA ~-SUNSHINE: SS-SUSITNA STATION A. Less than 0.00005 mg/1. (EPA, 1976). Established to protect freshwater aquatic organisms, DATA SUMMARY -MERCURY (d) FIGURE E.2.63 1 PARAMETER' _MERCURY (Hg) Total Recoverable (lJg/1) 0.6HH44+++rHHHH;+++~HH44++++~HH~++++~HH~++~HHHH~++~~44++~HH~ · ·--· ·~ ·H-'t+I-HH-lf-HH--1-t-f+~+t-1-t..J+++-H--H-t-1-H-H-IH-lf-H~+t--H-1 A.-->-HrHHHHHH4441·++++~~++~~~~HHHHHHHH444444++++++++~~~~MH~~44~44~ Q HrHHHHHH44~++++++++~~~~HHHHHHHH~44~++++++++~~~~HHHH~H44444~ J-HH-f-+F+-1---H-1~-f-1-l---· -t--+'i-t-t+-1-HI-Hc-H44-H++++++~+++-Ft=+-~H--'HHHHI-HHHHH44~++++~ SUMMER ·wiNTER BREAKUP • MAXIMUM -MEAN • MINIMUM *OBSERVATION D-DENALI V-VEE CANYON G-GOLD CREEK C .. CHUL'TNA T-TALKEETNA ~-SUNSHINE SS-SUSITNA STATION A. Less than 0.05 lJ~/1 (EPA, 1976) Established to prot~ct freshwater aquatic organisms. DATA SUMMARY -MERCURY (t) FIGURE E.2.64 1 1 ... J .... 1 l PARAMETER1 NICKEL (Ni) DISSOLVED, (mg./1.) 0.004 • MAXIMUM -MEAN 0.002 • MINIMUM 0.000 *oBSERVATION SUMMER ·WINTER BREAKUP D-DENALI V-VEt: CANYON G-GOLD CREEK C-CHULITNA T-TALKEETNA $-SUNSHIN~ SS-SUSITNA STATION A. Less than 0.025 mg/1. (McNeely et 1al, 1979). B. 0.01 of the 96-h~ur Lc 50 determined through bioassay. (EPA, 1976). Established to protect freshwater aquatic organisms. DATA SUMMARY -NICKEL (d) FIGURE E.2.65 -1 --) ] 1 PARAMETER' NICKEL (Ni) Total Recoverable (mg./1;) 0.1 • MAXIMUM -.MEAN A'---------7>-• MtNIMUM 0 *oBSERVATION -++-H---l-) -\ -· SUMMER WINTER BREAKUP D-DENALI V-VEE CANYON G-GOLD CREEK C-CHULITNA T-TALKEETNA ~-SUNSHINE: SS-8USITNA STATION A. Less than 0.025 mg/1 (McNeely et al, 1979). B. 0.01 of the 96 -hour Lc 50 determined through bioassay (EPA, 1976) Established to protect freshwater aquatic organisms, DATA SUMMARY -NICKEL (t) FIGURE E.2.66 -J --1 ... J . ) PARAMETER I ZINC (Zn) DISSOLVED, (mg./1.) 0.2 • MAXIMUM -MEAN 0.1 • MINIMUM 0 *oBSERVATION SUMMER WINTER BREAKUP 0-DENALI V-VEE CANYON. G~ GOi.D CREEK C-CHULITNA T• TALKEETNA ~-SUNSHINE 88-SUSITNA STATION A. Less than 0.03 mg/1 (McNeely, 1979) B. 0.01 of the 96-hour Lc 50 determined through bioassay (EPA, 19.76). The suggested limit is based on human health effects. DATA SUMMARY -ZINC (~) FIGURE E.2.67 -] - --) . --] PARAMETER1 ZINC (Zn) Total Recoverable (mg./1.) 0.20 H4++++~HH4+++~HHHH++++~HH44++++~HH4+++++~~44++~HHHH++++~HHHH • MAXIMUM -MEAN •. MINIMUM 0 *oBSERVATION l t ~ ~ ~ -~ -.. _:~ .. SUMMER :WINTER BREAKUP 0-DENALI V-VEE CANYON_ G-GOLD CRE~K C-CHULITNA T• TALKEETNA ~-SUNSHINE SS-SUSITNA STATION A. Less than 0~·03 m~/1 (McNeely, 1979). B. 0.01 of the 96 -.hour LC 50 determi~ed through bioassay (EPA, 1976). Established to protect freshwater aquatic organisms. DATA SUMMARY -ZINC (t) FIGURE E.2.68 1 l 1 --------------------------------------------------------------------------------------------------, 17 t A PARAMETER: DISSOLVED OXYGEN,_ (mg./ 1.) 1"1' I~. if: ----1-1-1-++1-++ -.... ----·+t-J-+-1 14 ... -·+- ---- -.•. ~ .. J.-1--1--11-1-· -- -. 1-~"-~ . --.. -· .... . .. -- 12 • MAXIMUM ·1-+-l-1-+..J-·-... + -MEAN 10 • . ---· -· -· -.• 1-.1--1-1--1>-.!--1--4 ·-- ---1-1-t-~-1-..J-++ -+-1-++..J----.. . .. f-+-1--+-11--1-1 • MINIMUM -· ---1----· - . . -· --t-t-1-+-t ·-----. -·l-+--1f-+-t--t l·-----. -· 8 --,.- *oBSERVATION SUMMER · WINTEB BREAI(lJP D-lJEUAl.l V-VEE CANYON G-GOLD GA&:t:K C-CUULITNA T-TALKEETNA S-SUNSHINE SS-SUSITNA STATION A. G~eater than 7mg/l, hut in no case shall D.O. exceed 17mg/l (ADEC, 1979). t::~-; Labli::olwd for the protection of anadromous and resident fish. DATA SUMMARY -OXYGEN 1 DISSOLVED FIGURE E.2.69 - l ] . -~ l PARAMETER 1 D. 0.1 PERCENT SATURATION ----· -.. --... ---------------H-i~-+-JH--1-.1--t--1-.l--_.___.._ W--1--1- 120 t-+-·H--!H--t-+-t--·-·-· ----1--+++--I-~ ~-4~--1-+ -l---------- · ---· -------+-l--t--1--+-t-+1-H-H-H-t-t-H-H-H-H-H-H-H-t t---~-+--+-1--1--4-+-+-+-+-+-+-+-+-+-++-t--+-+-+++++-I-+--~'-1 ---1---- A--;;- - --· --· --. -,-;;, ~: 100 • MAXIMUM . -------1--1-1'-1-+ -MEAN ... ··--..... ------· ---+-+-1-+-_.___.__.l--1-~-+-1-1---l~-+-1-t-~1-+-l..j, eo .... ·--. -... -----1--+-11--+--l-1--1-. -· -.. •. --+++-?-+-!·---· ·-· ----.. ---. +-+-t-+--if-1-· ---. ---t-t-+-1-~++-+------· ··--1-1-H--lH • MINIMUM ...... ·-... ------· .. .. --1-l--l~t-4--l--· ---.. ··----· .. -1- -!- 60 . -.. -------1-+--l-1--1--l--~f~----··---. ·- *oBSERVATION SUMMER • WINTER BREAI<UP D-DENAU V-VEE CANVON. G-GOLD CREEK C-CHUl.ITNA T-TALKEETNA S-SUNSHINE SS-SUSITNA STATION A. The concentration of total disolved gas shall not exceed 110% saturation at anypoint. (ADEC, 1979). Esl<~blished for the protection of anadromous and resident fish. DATA SUMMARY-D.O.) %SATURATION FIGURE E.2.70 --] 1 1 PARAMETER: NITRATE NITROGEN, as N, (mg. I 1.) -·---·---++++++-H • MAXIMUM ---------.. -.1-J.-I.....HI-I---I--1-++++1-+1-+f-++H-H-H ----_ .. 1-f-1-f-H-11-1-1-++ t-+-H-t-+++-t-1-1--11-.J-1-----· -MEAN ---·-. -·-· .. _, ~ -.. ·------·--------···- --· _ .. --.-.LL-L-<-1--· -------· + -f-H--1-1- .... ·-·-------------·-· ... +++-1-+-1-'H • MINIMUM +-1--1-.J-1--.. ··----·· --.. ----. --+-HI--+-1 .. -- --------" ----·-----.... ,_ ~ . --------· ----. --. --· _: -------·---· --· . -.. .. ------ ----------------------· -----. ----- +-1-11 ·++-.... . .. - -·--------- *oBSERVATION SUMMER 0-DENALI V-VEE CANYON G~ GOLD UREEK C-CHULITNA T-TALKEETNA S-SUNSHIN~ SS-SUSITNA STATION Less than 10 mg/1 (Hater supply). (EPA, 1976). E::; I. cJ), I i sl1'"d lo protect water supplies. DATA SUMMARY -NITRATE NITHOGEN FIGURE E.2.71 0.4 0.2 0.0 . 1 1 PARAMETER: ORTHO PHOSPHATE, ?S P, (mg./ 1.) -1-- . -1-- . I -. -· ----.-. ·-.. .. ---I- ···--····· -----1----.-·------- -----------------------.... -------· ---- ~Ht-+-f ·---+ - --· --------~ -l-H -~-t--l-l- ~-l--l-1---1---. -. ·- ---·--.4--J---l--l---~~ ... --. --·· -· ------~ -------------- --· - . ---l----· ---.... ·-· ---.. ------ • MAXIMUM -MEAN • MINIMUM *oBSERVATION SUMMER :WINTER BREAKUP D-DEUAU V-VfE CANYON a~ GOLD CflEEK C-CHULITNA T-TALKEETNA ~-SUNSUINfi SS-SUSITNA STATION No criterion established DATA SUMMARY -ORTHO PHOSPHATE FIGURE E. 2. 7 2 ) ---------------------------------------------------------------------------------- G Can t we l l SUSITN A RIVE R DR AINA GE COOK INLET ANCHORAGE LOCATION OF TOWNSHIP GRIDS IN THE SUSI TNA RIVER BASIN I. Suslfno 2 1-i~h Cr eek · 3 . Willow Creek 4 Little Willow Creek 5 . Koshwitna 6 . Sheep Creek 7 . Montano Creek 8 . Tal ke etna 9. Chulina 10. Susit na R ese rv o ir I I . Chulitna 12 . Tokositna 13 . Kroto-Trapper Creek 14 . Kahiltna 15. Yentna 16 _ Sk wentna 17 _ Happy 18 . Alexander Creek FIGURE E.2.73 ' ' '<· /--../\ ·, / / _,.--·T--·, .. ,.._i I I v _( ---' '" ~\ '\ ' --- ' '\\, \'\' 1 ·,)BORROW ~/_I SITE F \\\ ,\·.2 )J ' l ,/ '~; WATANA BORROW SITE MAP / ~·-- ,-------' ·-• ",rr::t_rl c _·: ~ -~ 1, r ,J " // c:. t -~';l=:-r:' t ./" I -~;"-r / SC /.LE O!"""""~~·~;;;;;~B MILES LOCATION MAP LEGEND [_~~ =:J BORROW I QUARRY LIMITS NOTE I . MAP INOE X SHOWN ON FIGURE 6 _1 SCALE FIGURE E.2 .?4 l ---] 1 z 0 fi > w _j w (/) 3: 0 ~() u ~ ~ -'l-() u -() o' . f-cP l(j () () ?.> t:?J ()() f-/' I I I It I I I I 1 I -l l ] 1", ..... ........ .... ' I J . I L--~ ---~--_..._ ... _ ~---.... ....... _ . ....,.. --l ~~, I t I. r-'i-H· l ,tl \1 \J ()() aO ()() 9. I I I I I I l () ~I I I I I I .t t () 1#1 J I I l I II t () ':)I I I I I I I I STATION CROSS-SECTION NUMBER 32 RM 130 l 1 ) l ' • I I 1 • I I I • l I Q=52,000 =.J r I : a=34 5oo I /1 I Q=23 400 ,' .. f. Q;j7 000 r : Q= 13 400 \--]~ Q= 9 700 '--Q:: 6 OOO(e) I I I ' ()() ()() 0 () tl5, I I I I I I I I ~~I I I I l t I FIGURE E.2.75 z 0 2200 WATANA DAM CR E ST ELEVATION 200 0 ~ > w ...J w 1800 ~----/ WATANA WATER LEVELS 16 0 0 1400 1990 25 2 0 ,.., 2 15 )( I .. I -0 w I (!) ,, a:: <t 10 I :I: u ~ I 0 I I 5 1 1 1990 10% EXCEEDENCE PROBABILITY ----50% EXCEEDENCE PROBABILITY -----90% EXCEEDENCE PROBABILITY 1991 1992 TIME (YR) WATANA WATER LEVELS AND GOLD CREEK FLOWS DURING RESERVOIR FILLING 10 °/o GOLD CREEK FLOWS FIGURE E.2.76 - - - !'""' - f""". """" !"""' I - 50 40 (/) I&.. --~ u I&.. 0 \ (/) 30 c z \ <1: (/) ::I 0 ::I: 1- z -20 1JJ t!) a: <1: ::I: u (/) ® c ---- 10 0 5 10 15 20 25 30 AUGUST LEGEND: NOTES: ® --···- AUGUST 1958 FLOWS FILLING SEQUENCE I, AUGUST 1958 FLOWS-WATANA MINIMUM STORAGE CRITERIA VIOLATED FILLING SEQUENCE 2, AUGUST 1958 FLOWS-WATANA CAPABLE OF ABSORBING HYOROGRAPH I. WATANA FLOW 84% OF GOLD CREEK FLOW 2.. RESERVOIR FILUNG CRITERIA EXCEEDED AUGUST WITH SEQUENCE @ 3. NEGLIGIBLE CHANGE .IN DAM HEIGHT DURING FLOOD EVENT 4. MAXIMUM RELEASE AT WATANA 30,000 CFS FLOW VARIABILITY NATURAL AND FILLING CONDlTIONS DISCHARGE AT GOLD CREEK FIGURE E.2.78 - - -I ~ 0 0 'l-::l -NO J..L."i't\-3l~ 0 _s J L 0 z 0 0 ILl 1000 9 IL 7 6 ..... 4. UJ L 0: ILl a.. 0: ILl 1-100.---. ...... ' ' ' l J: ~ i-~-;i~-.~~~~~~~~~~flJ~r-·i~~i:;~~~stHll~~it~.k~;~-i~-ILl a: <I ::;) 0 UJ a: ILl a.. UJ z iij 1-UJ z w 0 0: 0 ::e l •--··· L-. 10 9. ~-~~#~_~4~41~-~~,c~~~~,~~~~~~~ :-ttfi=:ftff}:ftf >J !Jij:~fF: := ;~ .:-'-1~ ~: . :tttfft1":'4 .. -:":'l"':~m"+'P~*H"4"±-"~':'t=r=:H~t;:;!='++'i:-::=l:=::t-4:-t==t:--!:'~Y:,t::t 4. 1 .. L .. LJ:±f_;:LL..L.+-w u.J.._J:: , . .I , :r' .. , It~-...... -t·tF ~-.:L:..l_Li:LJ' 'N,i-Fr·rrFl.fl:r;:::t:•lll: JJLt-, ~~~~$M~ FT~i·-f ~. j ;~T-i I .f' 1-•"""f•~"-l---t r;,-' I r· --~--· ·: c·rl-! ...... _,__ . '···-_...---r~ j .++J ' I 1.! Jifijti!t~h-,._.+1--J~kJ....J--t.-+-+, I 1 LL L~. 1 fJ I 0 { [ ( l I N I I I IQ .,. S~3l3Vi Nl Hld30 { [ t I U') L L 0 N N N NN CIO CIO CIO CIO (0 ~~!?~!? >->->->->-w ..J..J..J..J..J 1-:;) :;) :;) :;) :::::1 <I .., .., .., .., .., OCIO,._,._IOIO NN N--zl ~ = ,... -o-a~ = ..... j: . . .. C) <td~;!~~ LIJ t; t; (/) (/) (/) (/) ..J I ! · I ~ ~~~,, C( I : 0 ' : I l : (_ l t f/) t-zz LLJ LLIO~ ~t-LLJ <tOO:: _aZ:J -en <tt-<( zXLL.I ,_LLJ;:e 3~:J ~ ·. t-"-LLJ-rn __. z (. 0 CXl N r:r:t ~ l:l t.9 H Iii - -610 600 ~ ....,: LL z 0 590 ~ :> lLI ..J """ lLI - 580 -570 127 23400 17000 13400 9700 WATER SURFACE. PROFILES AS DETERMINED BY HEC li UPSTREAM LOCATION OF SLOUGH FLOW r ® l ,.Ji MAIN STEM -----:"'\ ~ ~t;~) SUSITNA RIVER I S.LOUGH THALWEG -.J/ THALWEG f \ . PROFILE Ul ·J......MOUTH SLOUGH WATER SURFACE PROALE (2) @ CROSS SECTION 128 NOTE (I) TAKEN PERPENDICULAR FROM MAINSTEM FLOW (2) ESTIMATED MAINSTEM DISCHARGE 1200 CFS 129 RIVER MILE SLOUGH 9 THALWEG PROFILE AND SUSITNA RIVER MAINSTEM WATER SURFACE PROFILES 130 FIGURE E.2.8l 2190 - 2180 2170 2160 2150 ...J IJ.J > lJJ ...J 2140 a:: 5 > a:: w (/) 2130 IJ.J a:: <f z <( 2120 t- <f :3: 2110 -2100 2090 2080 - - ............ ' ' II ~---' V I ', I ' I ' I ', I ' I ' I ', I '\., ' / ' I ',, ,::,; ~~ MIN. YEAR ' I ' I '\ I ' ' // ' / './ OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP WATANA RESERVOIR WATER LEVELS (WATANA ALONE) FIGURE E.2.82 eo .. ... <>so 0 0 ~ 20 10 0 Z202 Vr I I I I _ _) 0 1\ \ -l.DIJ \ I \J L -----~~ VL "' ~T FIU::ILITIE~~ AT FULL CAI'II<CITYj \. »ftl l ciOTLfT"',:C.LITIE S Of'£RAT111i (MATChiNG INF1.0Wl 10 115 z.o TilliE (OolYSl 11 50 YEAR FLOOD (SlMIER) ~ 10 Z200 r-----+-----+-----~----~----~----~----~ Zl98 -2196 1-. IL z I i ~ 2194 ~ LWA:X WSEL. Zl93.0 ~ 1 v-'""'-1 I 5> 2192 \ . I I ~ 2190 1-----1------t--1; /-1-+--1' --+----: ~\-----+-------! 2188 1/ i 2116 -+--.--..--''V'/ Wt-£L F~~i:=i / ~ERHOUSE AND OUTLET fliCILITIES 2184 0 ' OPERATING (WATCHING INFLOW) 10 20 TlWE (OATS) 11 50 YEAR FLOOD (SUMMER) !5 liO 180 ..0 140 ItO ; ... <J 100 0 ~ ~ eo .a 40 20 0 Z202 uoo Zl!l8 2196 1- !!; ~ ;::: Zl94 ~ ... ...J ... oo: ZI9Z 0 > '"' ... ~ Zl90 2188 Z186 Zl84 A rroorFLDIJ I I I I ... I ~ J ~ I ~ INFLOW j'-r::rrw MAT~ I'--r- WLDWl/'! I /r:-:~IN !IPILLWAY -----~ OPERAT~G ~~O~jL~SAT 1 \_I FULL CAPlliC ITY l 1 POWERHOUSE .lHO I OUTLET FACILITIES jEIIATj (MATCHING ~FLOW) 0 II 10 115 z.o TIME (DAYS) 11 10,000 YEAR FLOOD !0 ___£MAX WS: L Z 193.3 \ lf----~NFLOW EXCEEDING OUTF\.DW C~CITY I \MAIN SPILLWL OPER...JING (MATCHING INFLOW) I I KtrUTLET fACIUTIES AT FULL C~TY E RHOUSE AICl OUTLET FACILITIES OI'ERATINii 0 (MATCHING INFLOW) 5 10 IS 20 TilliE (DAYS) 11 10,000 YEAR FLOOD WATANA HYDROLOGICAL DATA SHEET 2 50 ;:: IL z 0 ;::: ~ ... ...J "' '"' ~ '"' »! "' '"' ll5 MO liZO DO 140 ; ... utoO 0 ~ ~ 1.0 ... 120 i'--/ ~! ..rOUTFLDIJ ~ , ~ow-, I \ ·;· \; r~ ~ r\ I ll\-EMERGENCr ~\\ I OPERATING \ . I\ jl \ ' ' I· 1\ I \. I I I I I eo 40 I I I I !/ MAIN SPILL-.Y OPERATINii ~~POWE~ AND OUTUT 0 ./ FACILITIES AT FULL CAPI\CITY _,.. TLET FM:IUTlES 9f'EIIATIN~ 0 • 10 115 10 10 TillE ( o.tmll PROBABLE MAXIMUW FLOOD uoz r---"" ~ 2200 I--EMERGENCY --~ !198 OPERATWG ~ \ Z196 \ I I 2194 I \ \ tlliZ ~ \ 1\ !190 \_MAIN SPILLWAY, OUTLET FACILITIES 8 f':OWERHOUSE OPERA niG !188 !186 r----h;H---+---+--t---t-----lf--------1 f.----""' ~OUTLET FACILITIES lOT FULL CAPot.C ITY 2184 I 0 II 10 Ill tO H 10 ll5 TWIE ( OoCI'S l PROBABLE MAXIWUW FLOOD FIGURE E.2.83 - -' 1110 -1115 150 ~ I 135 1/ I IZO --... UJO!I g E I f-...u. I rl I f 110 c ,_ ~ '1"!5 v !/ l! ll ,. .. so / ~ / v 4!1 ~ / v v / I ~ v p-~ IS 0 1.~ 5 10 20 50 100 1000 10, 000 ~ , ...;..o PERIOO (TEARS] INFLOW FLOOD F REOUEHCY - .... WATANA INFLOW FLOOD FREQUENCY FIGURE E.2.84 J J .,.~~~~<----,-, I ' --T --~---._ -_,; _: "F . - -~~-~-=-..:~....:....;_~--;._:. A---~i.-::.- :--"' -=-t==~--~]=--_ --t----+ -j .,-.; ·r::=-·:.;..; .. 1 - :....:..J.,.=.. +-=- ~--=-r .~_--:, --~ --. -I . -=x=::: -· I ~-. - !cC -----o' '-"' -'} ~.0.: ---~-:--. =-----{-.-: ~~------~-~-_,--~----~:_=_--.1 -~---~------~r~---- ... .IANUA!ItY --t-------1-~---~ . -- --- ~-~ -__ ......_;-.r--:=-- _,,--i"---- .--~ -~.,=-=i --= _ , .-:. 1 -l -- _;:_~ ---__ -:.-1-:-. • . i":-..T~--1 <- ~ 00' "•l OISCMol•&( (CXIIII.li._(O Oft f•Cl lOI[O .I UN. !--~-----+-- ;- -- ..._ . ~~~~k-~~~ ~;i~-~ll""'l~-_.,:..1:;-~---~-~-::;;----~ -""--.-':-] -'- --+- -- J~~~~-~-~-;~,'~-~:!!~--~-~~~~~~-~-'~'-~-~~-~-~-~~-f;~-~-~-=~·~,~J~~ :-~: ::::--"j ,-~-_:,;,_o F -:----i ----- •' =---;~-=-=7: _'--:-:--::-r.-:-_ .. ... ,... 0# T-DoW:......: fOI.I&I,.L(O 0111 l•Ul .. NOV•M•• .. ~~---~~~-------;-1·---1"-_-------.-, -~~,_ ~---+-~- -+- -·.:::f . ,-·-= ;· - -:-'-~: -:"":._~:~--':=....:.t:..:_-~:-:_-:--,-~-----=..::. ... . . -::1--: : .;_ -_-:i - '--__:_:-' -!-="" r---- +- ---r:--- ' ~-----r -~-~-_cc_,--L:.O. .::-:~ ~----~,-._~----~'~~~:; :~:"--=--''ik ="-. '""_:_""~'-==,:3=_~+.-,~c,_:_:¥~-=f---- o' t:="---, --~>=f':--'----"I -• +- .. : •• ~ -------~-----• -,_ ·_ -l=: ---:--4 ·-f-.- p~ -~: -_ ;~_:-!;,-_ --~ J 1:::--+-- __ ,,-:=:-__ '~ :----- I _-, 2 _-_,_-----·-:----:: .-=-::-::-::-.:-.-----'--i ':------'7-". ---+--~ ---=-=-'-"1'_ ·f • I I I "' 00 .IULY --- '~ ---~'-=~"'--~--·-·--,--- ..... -- --+ +-- ~--- ----+--· .,'-+--~-.~ :----::--+_ i __ ' -'---.• -:1 __ --=--::::j__,:-C-o:-__ ~·=-.---=-:~ __ = :T-( --,----: ·c___:______:_ --i---] __ -c"T""_ -------;...1 --,. .. .. Off T.-( -..c-.: (euAf.L(D 0'1 t•U:l~ a•c•M••111 ---1 _.___ T ,-_"'7'' ___ o.t_:-= ~=---~:____:,~=>--=---=--__ -; __:_ .. :~""'"~-~~-~-'-i~i'£~~ -;·~_:_i~~~f:___~:-i~-~ --~~::_~--~+-=~= -1 -~ ~-;~---_,_,, -·=i --~ -- -. :..-I ~ - -::0-'~ •--!-" T -- -=-'='--'~~__:; ~-----~!?=:-= -~;:j---"'' ~ ... J~i--~:~--~-::1-1--1--+!-11~-i-~i--~ ~--~-~---~-=f-E-~" ... 'lot# T...: DISC-...: l:eu.ALL.(O Cia [liCU .. MAIItCH ' ~,; 4 '~ @3 j~: :~ -o' __ o [ .. ;~~~:: -~-----:: • '-_::::....:!. ~--__ ,.;::-r ~---~ "":3 1----:--:--:-_ ,"---_ ,.--':~:l-o:.'"'_cc:;:o-~-'""~*~-~-~-;..~--~+,,--1=_-~-~~-;.;...~f-: ~-~ "'i i-i=::l·---··--1-~.--1 E .. ,_-7-~'-- :.r-~; ~0.:--:.: -i :-:. . .:. ---~--=---=-=- --:-!]-~-~I~----~o :=~ --l --• I --,-- ~ ~ ~ c ~ e ~ ~Of' loY( O l SC "A.~( f OV.t.lL ID Oft fi CflQU) AUDUaT I 00 -t '::-"--:.Oi -~'--;_--::}_'--0-::'---:---"=j -'-.:~:-.o.T:":':7--i --= ... _::e-:.::.:.:;r-=-=-:-:=.::'-':{c--:-::'-:-:--:-r~~-:_:~_:~ __: ~ Df' T..C .. t.( ..... M I...,.,.._Ll. 011 I•CI:I.:I ANNUAL .. · . . ' '· • ~ I ·· -~~==-:-:.....::.....=.~ =· ----~~---=--~ ---~-----~---. = '=-=-=~----·---=-! .:: :--~-~ -.--.. -. -:-::-:--:-.-:.---::-.---:--.:_;....-=~~ =---=-~-::-~ --___ -:-' ~ =4~~--==--~--.=--:--=---=-~-:::::t--= _:?-_" := All'lltiL ;...;. .. ·~-:<~~ I"'--:.-=-~~-=--:;.-r-:-:: . -----:: ~~--=t -::-·-:=-~~ t==~ .-! ~-----"¥" -~-_: --'1 :-"-:-4#:-~~== -- ~-;;: -:--r-___ -----c _ -, ,;. _ -_,___ --j--•- MAY --:,-·- ::---:-·~~--'==-~1-::.~:. --~---~~_: :;:-~_:-:: -~~--:;:= ~'+----' :_---_-~--_--_-"-'-'!,_--_-: ~:_--_c_T~---~--_-_----:r=:-.--_-~--=-~+,_------ ~ 01' l UI( Dl"( .. .t.JU( (0UALL(D Of! (•CllDI.C ··~T-Ma•llli ~: ----POST -PR OJ ECT 1.. CIJIIV(S W[ft£ CEIII[JIAT[D P'ltO• 50 'f£US ftCCIItO 0' MISTOfUCAL A•D II.UlATt:D AYI:IIIAG( .OCTMLT P'LOWS.. '%.Of' '...: o.•c"'"'11" tou.&I..LtD 0111 [•cu:-. acTO•• ... MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT WATAN A FIGURE E.2.85 J . . -: . ... T .. ...C.._. If~-ll.CU: .. JUN. "1.,. Tllll Dtt.e""'ltM r~rc 01111 r•cu:001 NDV·M···R I .. -... ~~~-.............. ·-~ ...... U.IUtY -"'t • T..: ~ r-....u..aa • l-c:a..~D JULY '1. til T..C Ol•c.......: lOVALL[O tM f:ICUDED a•c•M••R . ; : " J ! • -! . -· : MA .. CM ... T .. DIKM&ItSI: l~ mt ~CIUI AUDU•T ii ~- ,-- I! • -~ ---~~,,-_,.o • r-~-r--- -• . ~~' =-== ., .. .. ;. ;. ,;, .. .. ... .. Ill' T.r lHSCtUoa•t IOU4L.J..ID C. l•CU:KD ANNUAL ! ! ,; . ,; • _____ ,. ,.,T .. ~r~••u~ ··~T·M-·11111 ..... ,__~,~·-~ DCTD••• ~; ----CASE C I. CUI'i£5 ft"£ &ENE,_ATED 'lltOM :SO T[AJtS •£CORD Of" MISTOfi'ICA L AND II.ULAT[.D AV[ .. Aii( ..O.THLT P'LOWS. MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT GOLD CREEK FIGURE E.2.86 ... ..,.,,...~·~·-·--•a v••-• i i i i i .. ., ~ ~ l:.........ull Cit lxcaaD fi••IIIUAIIIY . . ... .,_-~ .. ,...,... ••c••••• i i i .. . .. . i i ! . .. '1. W T-....c..,....; I~D ~ UCU: .. Au•u•T .... T-..C...._ IIIU.AU..oU -~~ ANNUAL i ; . .. . . i i ! .. . ..WT-~I~DIIIt~ ··~T····· ----CAS E C i ; ! .. .. . i I ! 1.. ~ KIIEAATI:D ,.MIM ~ ~ARI ft(CCitO ., n•TM£StZ£D AltO ll.ut..AT[D AV(ItM(. .. TMLT f\.OWS. .. ·-·-·-· .. -'lofWT .. ~I~I-~ MAY . -.. .. ., T-..-c-.: I~D • PCC:I. .. DCTD •• III MONTHLY AND ANNUAL FLOW SUSITNA DURATION CURVES RIVER AT SUNSHINE : i i i .. : . FIGURE E.2.87 L _ • • 40 • • ,. .... ~IMK,.,.,._I!:~·-~ -.JUN. ., ,. 'II. 01 ,._. DnC~WAM .:-... .. u:o ~ ~~ .. .,.,..~I'WIIl...U••r ..... ~ .... UAIIIY .. .... ,. .. ~,.......u8-~ "'ULV .. 01 T .. DtSC...._ l.u6&...Lt0 C. «•cu:-a~ a•c•M••~~t MAIIICH 'lo 01' T ... DISC:MAitU II:OUAI...L.lD Clllt UCU:IIIDI AUDU.T ,., 01 , .... sc"""'" r~!.lD c.~ ncuao ANNUAL AIOIIIIL MAV '1.., ,. .. ...c ..... ~~~o aa c•UL~~~» ··~T·M .... 'lo., ,. .... sc-...; lltuAU....lll oa r•cuDC DCTOIIl.llt I. ---...:-ll'tii(),,(:CT "UM ----CASE C l. CUWVI:S K•EIItAT£0 'lii:Oit )0 Tt:MS JII[COIIIID Of" MIITO.UCAL,IT.THESUZD AIC) IIMUL.ATED AVUtA&( **lHLl f\..OWS. MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT SUSITNA STATION FIGURE E.2.88 - .... E - .- - WATER TEMPERATURE, °C 0 2 4 6 8 10 !\\'---.....,.-+--,--:-...:.....,.._+---1-'-~-+-~--+--,-'-· -l L . + . . ~- -\ ·-· -·6--l------:-[--c--i-/ ~:~\.\.::~J~.::::-~i:-t~~~~~.;-~_:-_t,~.2~~~~_=-+-+m~7...§i __ --1---;r-:::-~.~----:---=.+-,:-~~~~ ( ' ' I ~~~~~-r\~-+~-i~~~-~~~~+-~~~~~~-+~+-~-'-~~~~~~~-+~--~~~~~---r~~ ~~-4++~~~~~~~~~~~-r!7~+r--J~~~~~~~~~~~- 40r-~-+.4-~-+~--~~--+---~----,.-f+-~,~~~-4----~----~ l I i I · HR11l.n F 1l.'KF i I ! • -· i ; JR 'S DF :NGlliEERS.' ~~~~~. +;~~~~~~~~ +'~r1 +1 ~~~~~~~~~·~-~~~UNPUBt~SHE91r+--~~ t I ! WATER TEMPERATURE PROFILES BRADLEY LAKE, ALASKA I I FIGURE E.2.89 MAXIMUM EL. 2185 EL2151 EL. 2114 mm::::m:::: :.; .. _.::::·:::·_.::::· ~lliiiilii.]!.i :.::m-:::-::~: ::::::::~t\ ::::::: :::::: :;::;::;} :::::::: :::::: ))}}{ :::::::::::! I:::-:::: :·,:,.::_,}} ,::}/(:=:.: \.::{:::::::,: m,·::::rm: ,, ,,,, ::::::::mmm ::=::::::=::::: EL.20 77 ---20'(TYPICAL) 065 :::::::::::: :::::::: :::::: ·::::: :::\:·:\ :::·:.\\':::: << ::::::: : ;:::;::: :::::: :::::::: :::::::: :::::: MINIMUM LEVEL EL.2 :} ::::::::: ::::t :::::: ;::::: MULTIPORT INTAKE LEVELS -FIGURE E.2.90 - - - .... WATER TEMPERATURE °C 2 '3 4 5 6 7 a 9 2200 1----2185 81273 MAX. RESERVOIR LEVEL I 2150 2.100 2050 ....: LL. z 2 2000 1-~ ILl ...J ILl 1950 1900 1850 1800 YR n 812.43 L,-J JULIAN DATE BASED ON 1981 DATA 2 '3 4 5 6 7 a 9 WATANA RESERVOIR TEMPERATURE PROFILES 10 I I 12 10 II 12 FIGURE E.2.91 (.) 0 14 12 10 8 6 4 2 0 152 I "'..;-' /'../ I I I I I / ;\_,. / 162 172 JUNE BASED ON 1981 DATA 182 192 I 202 JULY 2121 222 232 AUGUST JULIAN DATE 2421 RESERVOIR TEMPERATURE MODELING OUTFLOW TEMPERATURE ___ ,.,..., """" ' 252 262 SEPTEMBER ' .......... \..... -........ ........ ........ .......... .......... 282 292 302 OCTOBER FIGURE E.2.92 ,,... 180 165 150 """ 135 120 ;; ... ... 105 0 0 52 .... 90 "' a: ... :z: <.> "' i3 75 .. 60 45 - 30 '-15 0 - ...... ..... : I I I ! I I ' I ! i : i i I I I i I I I l I I I I I i I I ~ I I ! I ! , I I I I I I I I I I " -· ~ ! l I i/ ' ' : I I I I I I I I I I I ' I ! I ! l/1 ! i I I i : !)j. I I i ' I I ! I I i I !/ I 1 , I -.. i : ~· I I r -I i I ! -!. 1.005 5 10 zo 50 100 1000 10, oco RETURN PERIOD ( YEAl'IS l FLOOD FREQUENCY CURVE (INFLOW AFTER ROUTING THROUGH WA"r~NA) DEVIL CANYON FLOOD FREQUENCY CURVE FIGURE E.2.93 - - - .... 2190 2180 2170 2160 2150 2140 I- !:= 2130 z 0 ~ ~ 2120 ...J w 2110 2100 2090 2080 2070 OCT NOV DEC JAN FEB MAR APR MAY JU N JUL AUG SEP WATANA RESERVOIR WATER LEVELS ( WATANA AND DEVIL CANYON IN OPERATION) FIGURE E.2.94 -' ~' - '- - rr- ' - -! - 1460 1450 j::: 1440 ~ z ~1430 ~ w ...J lJJ 1420 1410 1400 OCT ' / ~ MEDIAN 'v""-MIN YEAR YEAR \ \ \~ '\. NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP DEVIL CANYON RESERVOIR WATER LEVELS FIGURE E.2.95 J !-'0 :!>2"0 280 24 0 ... ..._ u 0 200 0 0 "" 6 16 0 _, ..._ 120 eo 4 0 0 0 H 7 0 H 6 0 ,.: ... 14 40 ~ ! _, 1430 ... fQ Q 1410 HOO 0 -----, ~-u~r.) ~ J, , I ""Fl£'• I OUH L OW [~/ ~ I I 0 . \1 I ,r c.~·, ' I l'<fl.CJ'If-K 1 .,... )J.D <D•GE>I cY i ~L LII<.l.Y ) ~l hiG• ~~~ L,.r-~~ H'LOW V/~~~~ v ~T~i POKE RHOJSE 10 1&_ !0 TIYE: ( DA.YSI 1 5 30 PROBABL E M AXI M UM F L OOD I ltESEI'tV~ ELEYATX>fC IU.X. WS EL if DE:R<O E H cY -~-~1 I SPI LLWAY OPf:R..l.TI NII J .,POWER~ / \ OPER.IJ II-IG II 10 \ " 1& 10 TIWE (DAn'S) \ 1\ 15 PROBABLE I.I AXII.IU M FLOOD 35 0 ... 0 ~ ~ 0 _, ... 00 00 f4.0 ~ 100 eo &0 4 0 !0 0 1458 H:IO ~ I il IJ "'~-~· O<.JTFUYV!-y 1\ .· .;::; v 0 I ~ 1\ II •. J ~: '-IU.IH r LLWAY ~R AT I NG I ~,ER H OUSE .l.H D OUTL ET FAOLIT rS Cf'£RAr NI . 10 IS to TIWE (Ooi.Y S) RE SERVO IR R OUTIN G 1•10,000 YR. F L OOO ~ 1'-- l r POwt:RH ~, OUTLET fACILITIES .UCl WA.JH 5.1'1L LWA.Y Of>E RAT !ffi; I f'-w.u . .!,EL• ~5 0 10 15" 10 nwE IDAnl RESERVOIR ROUTING 1•10,000 Yll .fLOO D DEVIL CANYON HYDROLOGICAL DATA .. ..._ 0 § ~ ~ .J ... ,.: ... X ~ ~ ... _, ... IC 0 ~ ... on w "' r -----------------·---- ~ <10 ""' to l/ 10 0 0 H 60 H5 8 H~ H~ H52 H50 0 . ~-~L II ~, ~-I PO!>E~~ . OUTL..<I f"OLmu; CP£P.ATI~ 10 15 30 ' T IOf E (OAY I) R ESER V O I R ROU T I N G 1•50 ~ SU WW[R fLDOO / r ~~~~~L~~~ CP£RAT IN G I ( \. WA / WS£L •1-45 5 10 IS 30 T IW [ (DA YS) RESER VOIR ROUT IN G 1•50 Yl\. SUWWE~ F LOOO FI GU RE E.2.96 . • ..... . •I-- ..IANUAJit V . -.. --~ : ~: = -f ..,-.. : .. -._._-:~ ---h-t .. ..=-::-~-~ !=:=. ·' 1-:-· ... ......__. . -1-T-~· f-.:."10 __ _, t••.i,..._ : ... ]~i;_·i. -~~i~~~ -~:~-:..,~· ~ .. 11-~-~~i.o!"'!"ii-~· -~:~-~-~~~-~~~-i~i::!=i·~--~~~~~~=-~,=r-~-~~-~:·~~~~:· ---,;. -...... 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J=----t-===;: -~~--~1. -=---=--.;·:~-~-~::..:::_!:=-~-~~---=-:-......=.::~ ~-~~~~--~:~~=f=-..==- t-=-.· ---L_ ---j __ -~ .. 3: ----, ... r-c:~ •-..a.....:•Oitt:rcx:r.-=- ..IULY ... ~ . . -. . . _-::-.,. ~- ~:-~-· --= ""~-, .. , . . ~ .. -~,_.,,. -~:-:..:. ~~~:..:""~~=--: .-.:~~~~:~'t'- =-= ·- :;:'---,._. ... -t--..;.(_. ... ·--... ··-••<••-· c•c•,.,.••" ·~ -c:=--, • r -,-• .... --. •! I I --, ---,- ..,... I ---:-::-.;-::-1--;----;-- =3 + ·~~+~~~i:t~~~ F-'~·-=-----· ' . . . .. ... . . . ' --~ = .__ ri _ -=;::::. -·· ~-''-':o.:~:.~~, · .. ~·r_ .. ,,:.-_,~,--7:'. •·: • · ··~T·-. · T--·-- .-·. :i>--.. ~-~-~~l-===:~~-+=';'+' __ ._:,. . ~-==· . -·::t:=" -.. · -~~ ·+---1 ........... "'o-"-< .. ~ .. 1-..LJ:•-I ...::::I:(-- MA"-CH ":~:....:.'. -·~-:"'=~--~-;._~~-··t··· • ----'---:-.r-~ .. .. . . ~-~' ;:>"·_.c:. ~ '"''.-'c3~~:...:;::.*="=--7 B~~-=F~ ~~ .. .._ _, ,.._ ~---c l-.u•-c:..ar:"C-. AUmuaT ~~~'-·--· .-.. ~- :~~. -~-- '-" .·-y -~·--~----·~--·· ~.:::~_<+· ~~~~ -~, -..;: ~--~-~~~- :::=::f!, "=t=== . ... -___ , ~~3--~··.--.:-._-:~~~~:t=(.:::.l:~. _:_: ~;{;~ -~· :::c -.:f"' '. '='= -==:-r ~~·~5± ~ ·---:~ ..... ~-..--. J~~:~-~---~-~-~--i~:;~~-~--~--~'~lli'l~~~;~~·;;ll;·,~~~==~= -· -=r,:. . ~=-f ·· - - - --1 .. -... -.. _ •-c-,_.._,j-. r.··-- ANNUAL = :.,.i - c __ :c=-'-:--'-=' : '1 -.~1 ·:···! -~=--:r: I ~~~~l . ... 1---· + . . . ·~~~ -;~ . _,~,.,.._-, -~ .. --~ -· -: . . .. . . M A Y ~- .f---i : . . -.=....--~ f-' -. ··= ,.....-,::. ... . . . :::::::::!=?.· ~ -·~.,.,..------~ ----.. ~-.,.,-·~-~ ~~~F-·-.--~~---o~~ ---·. :. ~i ' '-· ···~---~--r--r--r--r·-·-·-r·-·-_-+T--r---+-T-- "'. _, T...o( ..-.c.---c. 11:-...........ce -C.~ ··~T·M-·11111 ~------------------------- L ----(-r-:w (CT f'"\..0. ----CASE C (WATANA/OEVIL CANYO N) L o..o-V'(S W"(fll"( c;(III(•"'T(D ,.000. ).0 T'(&6'S .-(~1:) 01 .. rs T OCtC.I.l.. .&.•O S••UL4TU .A.,( • .afO{ -c-'T ""'-T P'LOW'lL -I ~· -. : .; --· -:- - ---.. -'ll.W 'f'l>oo(~~--~- D G"T D•• ... MONTHLY AND ANNUA L FLOW DURATION CUR VES TALKEETNA RIVER NEAR TALKEETNA CHULITNA RIVER NEAR TALKEETNA ~· r-- -1---- FIGURE E. 2. 9 7 _j ::·:-~-j ~-~: ----~<~:-:~ :~ -:::: ----=--~--------. ------~-~-=-=-=- cc=i -+-- 3 ;. - =-=z-...=_._.::--- .. :: .. ]'I ,; -~ --, ---'! ----_--_-..£+: I ~~-: ~~;;;~;~-:-::~r;:.;:~~-=~-~:-~-~ JA NUAJIIt Y -: 1----;-· . --:-. --... -:~!- -+.~;.:-~~ ~:~.·---~ ·: . ·: . ' !-=='· ·--' =--"-t=:" . ~ .:..: . . '":"'":~~ -:,,--~';:-r=:==,: :·'~ p::"- --== ·'!-- z:·--=='·----·"'··· , ... T-.o[ Oo..C:........C IOU4c..L[. Ollllr •Ct.I.I:Cio ..JUN. ,-,,~ ---=TF .,.--------·----·---+--. . ---=·==--~:...-_..:-~l-:-: .. -:--.. ·j-~--,_-.- --r- , .. "; . ~.::..:.; :.-~E..-~.~ -: --~:--. ' ,----~ ... +._ -·-~ ·F' ----r---.. c=__; =~= ·-#_:~--~-'----~J-.::. _::~~' --~---=-=,-: __ ,..~ ... . pr•aJIII UA .. Y .... ~-----~· --ii· Et·-~----· ~ . . . ~ .,. .. -·-=-:==.::::-~~=-.. -=-"F""~:-.::: --=--1--:-:=-- -.-.-.-. .:~C::::::::!.:_ -+-: · . .::.:.:........:..:..·.:. ..• = ~ • .,:.-:? • .:· ~--=-~::=::--_ --=--:~::··!=-=-·-..,::-:-.:........,.--=~ ~-£~-~-·--~-~=-= ~-:.~:~~ :7 -::__ -· :=i':::~ ~'-:<--'=!~_:_ c ~:::_-=-~~-~~;="=~--+--,.~- -·--· __ , _____ --------~--·--i - roa _:_---: -:-:-T.:-:-:-:-=. .. -1-.--:-==:--:..:r --: -:--:----=~ ___ .... 1 "1. 0' T-t: OoS.Cou..t~c.t: [ou..&.I..L[. C. f•C[[OI:a --"''-=..:: •• ---~F=-i' -~·- ·: . ' --.:-..-: -~;...: . ' . .JULY -:c=F"' ,,--_ .,..~-~.:~:---~.: ~='=-=-#---- ---= .. _. -~! -~ ~ r--g---~-----i ' I -, ' ; ._:_: -; -~ ~ -~ - - .,. r--:--;- ~-· '=';f ---•===--1 ... ~~-~ ·~;,. -~--=--===i: .. · : . .. =• I . ; I .. , --~ -~ ~-; '-' -".' i-:-: _-.,_ .:-::r:(~-~~-=--?:r = __ :-=-_-:c __ ==.="--~=-:--, '-. -,-= ~ -"-"--:-'---: --:?3 ~ -=-':t-----;;_ • 2.3 :T:--. --___, ~--'-·-- ---------------,- 'I :, __ E~f :_-_=-::== . :r= .. : . ' ->----:---'"" = ···!c:_·--;:_;-_p::..::.::~_},.: ·--~ ---~~-4--:--- ·---~ . ., -.-:-.::a...-:-f -· •. _;_~~~(~~'_;~--~;~ -__ ;:_~~ -:;.:..-;: ·_ -~ ,.,.:.- --=: :'\- -1 -= ·=---~··.--~~f-., : .=ic_---_,~~- = ·-.:.~~.,;. :..... ==+'-=-~.--::1:= ~ :::::=:= ' I.:-.:..; ... --· ·.~ ·-··-r ,-',_,_::..1-=::~ ':1 -;.c~:, -1 --::- ANNUAL -------X:=: c . . .: -. -·-::---=-=-... -= ..:: -~~~~~~~~ --~E!~---~=~~--~~ ~---,.----r--------------- .· -~---...r.., TooC ~-'~•-r•c.u::- .._. Dl' ,.-< Do<J.C-.w f~i..l O ~ t:•c.r oca .... T .M .... .._., T-c: ~-.c. lGU.'ol.lo.l • 011 r •c:u: ... M AY ""'01 T..OC: EWSC.~c.« l OUA&....l.lO 0011 t•etl_. OCTo ••" ~------~================~------------- llill..E.S.: L ----[-~leT no. ~-----CASE C (WATAN A /DEVIL C ANYON ) 1 L Q.lll.rt.S •l"[ IO[.(JtAT(D ,.~ 32 YEARS •£~0 0,-'"ISTOttiC &.l AaD S I WULATU I .A.Y'{Il' ... IO[ ~'T""'LT 'lOW"L. MONTHLY AND AN NUAL FLOW DURATION CURVES SUSITNA RIVER AT GOLD CREEK FIGURE E.2.98 11 ·_-·. ~ .. :1 ~-,-~ ' .E=i . ~ ~r:J:_ .. ,.... : ~ .. -: :r::: ;fc~l=t ~Jr§fi t .J:gifmtlrdW --~ -...-:: · . :. j .. 1 · -• :I -c~ ·,.:_c :__:~-F"=~--'-f':'o oo "-"'* _,:~·:ci.'~ .... ~--=· ~~ ' -_, --. "--;" __ --'--j - '··r ·-· --·---=-~· ---,,~_-_,_ --~--,~···~" --_-_ :. -~r- -·-.·~~--.·--~·~:~~--+·:__:-·:__:-~-~--:__:-~~~~-:__:·-~+:.:=:__:;~~~-----_'-_'.,.~·~·-l•C::C:I[- .JANUA.RY -: 1- .. . . ' . I <~ ~ ~~:>~~-' :~::,:·~~~'~ 'c::cc_:__:_j__:__:_::--~ ~---='= -~1== --------;.'--¥ ·--:~~r:· .. ~ _, l""( .. K ......... l........_Ll. OOt l•«l~ JUN. ---·-:. .. ---~ --~-~ '-.... -....c .......... f-._L( ... (..C:.U: .. -~ .. ,_ ------~ . -----------------=m~~~ --~p~~~J1 • '-· •or--,, T-:- ---'-----·--·!------- • -. ·-~--. - --==---:.:=-!=.-~-. ---,:-f;~== ~-=----=: ::.~--------- ---- --• • -o -: :-: i : =:·· -:;::--=::-:;~ -...:.. . -. ~---:....:..~:._ _ _. __ ·§-~=-:.=.===:.~ ~-~-====--:.-=::o· ~--. -==:;":;:r-:~ '--:7--::::-~L~.:.:: '-::=-.-= -='"-7.':~·'_--:·::'"::---+:: <Ot ~--:-~::~=~~:--~~:==~~+=- ~ f1l' t....: o-.1.<~~ ro..o..o..t.Llo coo r•cu:Ditl ..JULY "'.-t-c ~--.r •-u•-r•ut~ o•c•M••" N 0 V • M~-~·:__: .. :__:___ __________________________________ _ ------------ .:r=··- --·•_-1~--1 ------i , .. ~:1~~-~-:~~~~,·~:~;· '"';'·~~-~~'~;'~~--~-:~-~~--~---~~~-ill.!''>fl,l~l- :~~-:-';~-~--0.-------J·+~-: 0!1'~~~~~~~~~~~~~~~~~~~ jj;f[s.ftf;: r IE :e ro _ ~ ___ c :: .. ;.=~:-:....,! . o.:-: -: =7k: ~-r .=o~~ -----.-:-1 •. '...,;: ',_ 'l' .-- :F-. - :;.~:....-:_-~------~~~-=-:..=·:_~-+-~:-.:-! :~ '--"=-~-",! -~"'=~'--~=i--':c _'~o --'c-i~:=:=:-c''--'-i--.c 101 :.:..._..:....::..· __ • i:-=--=-.:: g --::-:-:---f·-= --=..:.:..:=--:=1~ _- ,;. '"'~'----7,,:..:--_.:..c::~~-'------=":-~ =-==J== .. --~ -=-.. • -· =1----· -~:-::-:-:-:--: --.--. ------ "., ......... -'-_.... f .......... LI•-(eUf~ --------------------•a r-----:::::1:: :r::== lt'~i~~~~:;i~~ . . . ~ . . . • I ; ~ . • ~ . ' ......... '=' _ ____._,,____, ,_- =--...:.....:.::.· -- -&,.01 T""'[ .. K ...... ..C (Qoo.I..L.I..J..(D CJIII(•Cf:f .. ••PT•M••" r ~ l ---1""011::(--C-.If.CT '~ ---~ CASE C (WA111NA/DEVIL CANYON) I ._ "-"'•U <lo<O&T[D "'"" )0 .,. ••• "''--""""': I I T •h•(Sil(Il £1010 SIII'Ut..ATCD &'ll't•"'-"'1: -c-T ... LT "-DWS. i. . 0 MA Y "1,., Toooo[ .. ~ lou.t.I...LC.•-. ll•a:J:-. OCTO •• III MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT SUNSHINE I ! I I i FIGURE E.2.99 J .. _, .. ~ r--o¥{;:_~c ~~--f:=,,,~:t ---- -=a~ -c:::F------•r-, !'"'> i --=; --- ' -~ -~-:. :~~=~-;--_;~~--~~-~~: -'"J;.WT-.:~1~1-~- ..IANUA .. Y ~ 1-...... ..:.__. . . . --:+-~~:~~~~ -~-~}=:· ~~,~- ~~ --=~-:· •. r-:- : .. :- -:-;:;.:--:-=~:~-.--::·t=--:--7. .. :-:-.r _-::: -... ~ "=£=:' --+- ,. .. '-< o-s.c;..........: •-u·•-••c-u~ .JUN. -~- >-- -- . ___ ;-'"'f"· ,-'-~,_-_ -----"'1-= :-'I .,. f---------+---. . : . -: . . :..-._ :.: ~-'• ·""""' -+ . . =-=:::.::- ----,,~ :=--t- --~~~ _,....., -.-: !-==:: --'==--==--' ' -- --~---~-=i=---=' -·~- '., '-< --................. la.Ut ... 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[11C.rt:.- QCTQ ..... \...!:!Q.IU: '----------CASE C(WATANA/DEVi L CANYO N)' I ~ C:.....-vt.~ '(•liO.AT(D f•:>oll >0 Tl:A.Jit"S •(~ 01 lo<ISTQ«<IC.&L. n•T,.!.S-IZ::CD .&lCD 'II'<UL.&TL8 A'I(IO.A~ W';)o(T"'LJ n...DwS. ------ MONTHLY AND ANNUAL FLOW DURATION CURVES SUSITNA RIVER AT SUSITNA STATION ;FIGURE E.2.100 I.<) 0 § 1\) 0 -i '§ 0 (.J) -Ul 3: § G") ........ r 5 § Ul § NOTE: 270 i ppt: 1000 mg/1 300 NODE .-NO. 27 330 360 390 420 450 4BO SlO 540 JULIAN DATE TEt1PORAL VARIATION IN SALINITY WITHIN COOK INLET NEAR THE SUSITNA RI~ER UNDER PRE AND POST SUSITNA HYDROELECTRIC PROJECT CONDITIONS · CASE 1 I .. 0 PRE-PROJECT CASE 2 .• + POST-PROJECT 570 600 FIGURE E.2.101